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Main
Date: 18 Jun 2007 22:55:51
From: Gary Young
Subject: Mavic introduces wheel with compression spokes
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Road Mag's blog had this item today:
"The [new] wheels, which are part of the Ksyrium family, use a combination
of hollow carbon spokes (tubes) and the familiar aluminum spokes found on
the Ksyrium. The front wheel has all carbon spokes and the real wheel has
aluminum spokes on the drive (cassette) side and the carbon tubes on the
none drive side. The carbon tubes act like a combination old fashion
wooden spokes, which supported the wheel by compression (like a stiff
wooden spoke on an ox cart) and traditional aluminum spokes that support
the wheel via tension. I won't try and explain it in detail here - but the
general idea is that the carbon tubes give the wheel a lot more rigidity -
plus they are lighter....
MAVIC brought out their machine for testing rigidity and put the wheel
though it paces. They then ran another five wheels from various
manufactures - these were all wheels that various journalists had brought
along - so it was a pretty random cross section. The new MAVIC wheel came
out on top. It was more rigid and at 1355 grams they are one of the
lighter wheel sets on the market (hey - the spokes only way five grams
each - versus an aluminum at eight grams - and we know that every gram
counts)."
=============================================
The full item and photographs are at:
http://roadmag.blogspot.com/2007/06/mavic-sprinters-and-climbers-take-note.html
or
http://tinyurl.com/2m59r9
Notice that Mavic rolled out an old wooden wheel at the unveiling.
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Date: 27 Jun 2007 08:09:10
From: Ron Ruff
Subject: Re: Mavic introduces wheel with compression spokes
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On Jun 25, 10:46 pm, l...@mochi.EECS.Berkeley.EDU (Luns Tee) wrote:
> For the angles present in a wheel, the cosines are effectively
> 1, while the sines are on the order of 2:1. The lateral component of
> the change in force from the two sides does not balance, being at about
> this 2:1 ratio. The difference is supported by whatever lateral
> restraint held the motion vertical. Without that restraint, the
> vertex moves laterally.
>
> The above assumed the the same spring constant from both lines:
> choosing appropriately different spring constants can eliminate the
> lateral motion. This is accomplished with thinner spokes on the
> non-drive side, with spoke sectional areas in the same ratio as the
> flange to centre-plane spacing. When this is the case, the strain
> experienced by both spokes will be the same.
Thank you Luns and Joe Riel... I thought I was in the twilight zone
for awhile there. This seems so obvious...
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Date: 25 Jun 2007 18:33:35
From: Joe Riel
Subject: Re: Mavic introduces wheel with compression spokes
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Joe Riel <joer@san.rr.com > writes:
> Ted Bennett <tedbennett@earthlink.net> writes:
>
>> Joe Riel wrote:
>>
>>> jobst.brandt@stanfordalumni.org writes:
>>>
>>> > Consider the spoke/hub configuration, a triangle, with the hub as its
>>> > base. The tension ratio is the same as its loading ratio. That is to
>>> > say, as the rim is pressed radially toward the hub, the length of the
>>> > left and right elements change inversely with the tangent of the
>>> > angle, (the same as the tension ratio of spokes, left and right). The
>>> > rim does not deflect to one side when radially loaded. This is
>>> > readily seen on any dished wheel.
>>>
>>> Not true. Consider the case of a dished wheel built with no tension
>>> in the non-drive spokes. Apply a radial load at a point on the rim.
>>> Both the drive and non-drive spokes compress [assume rim/spoke joint
>>> allows this]. The compression of the non-drive spoke generates a side
>>> force, which must cause the rim to deflect since the drive spokes were
>>> originally precisely vertical (normal to rim).
>>
>> Jobst is correct. You are talking about a theoretical wheel, one not
>> found on a bicycle which can be ridden.
>>
>> A bicycle wheel which can be used as a wheel cannot have zero tension
>> anywhere, nor can it have drive side spokes normal to the rim since the
>> drive side hub flange is offset from the centerline.
>
> I didn't say that this was a practical wheel. This is a simple model
> that illustrates that Jobst's (and beams's) assertion is incorrect. A
> radial force applied to a wheel with an offset causes (in general) a
> small lateral deflection. Some months ago I computed the ratio and
> posted it here, but I don't really feel like digging it up just now.
Here's the result I was referring to (from "Spoke Tension Question",
Jan 7 2006. x/y is the linearized ratio of vertical to lateral
deflection for an applied radial load.
/x1 x2 \
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Date: 25 Jun 2007 21:13:52
From:
Subject: Re: Mavic introduces wheel with compression spokes
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On Mon, 25 Jun 2007 18:33:35 -0700, Joe Riel <joer@san.rr.com > wrote:
>Joe Riel <joer@san.rr.com> writes:
>
>> Ted Bennett <tedbennett@earthlink.net> writes:
>>
>>> Joe Riel wrote:
>>>
>>>> jobst.brandt@stanfordalumni.org writes:
>>>>
>>>> > Consider the spoke/hub configuration, a triangle, with the hub as its
>>>> > base. The tension ratio is the same as its loading ratio. That is to
>>>> > say, as the rim is pressed radially toward the hub, the length of the
>>>> > left and right elements change inversely with the tangent of the
>>>> > angle, (the same as the tension ratio of spokes, left and right). The
>>>> > rim does not deflect to one side when radially loaded. This is
>>>> > readily seen on any dished wheel.
>>>>
>>>> Not true. Consider the case of a dished wheel built with no tension
>>>> in the non-drive spokes. Apply a radial load at a point on the rim.
>>>> Both the drive and non-drive spokes compress [assume rim/spoke joint
>>>> allows this]. The compression of the non-drive spoke generates a side
>>>> force, which must cause the rim to deflect since the drive spokes were
>>>> originally precisely vertical (normal to rim).
>>>
>>> Jobst is correct. You are talking about a theoretical wheel, one not
>>> found on a bicycle which can be ridden.
>>>
>>> A bicycle wheel which can be used as a wheel cannot have zero tension
>>> anywhere, nor can it have drive side spokes normal to the rim since the
>>> drive side hub flange is offset from the centerline.
>>
>> I didn't say that this was a practical wheel. This is a simple model
>> that illustrates that Jobst's (and beams's) assertion is incorrect. A
>> radial force applied to a wheel with an offset causes (in general) a
>> small lateral deflection. Some months ago I computed the ratio and
>> posted it here, but I don't really feel like digging it up just now.
>
>Here's the result I was referring to (from "Spoke Tension Question",
>Jan 7 2006. x/y is the linearized ratio of vertical to lateral
>deflection for an applied radial load.
>
> /x1 x2 \
>
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Date: 26 Jun 2007 01:55:14
From:
Subject: Re: Mavic introduces wheel with compression spokes
|
Joe Riel writes:
>>>>> Consider the spoke/hub configuration, a triangle, with the hub
>>>>> as its base. The tension ratio is the same as its loading
>>>>> ratio. That is to say, as the rim is pressed radially toward
>>>>> the hub, the length of the left and right elements change
>>>>> inversely with the tangent of the angle, (the same as the
>>>>> tension ratio of spokes, left and right). The rim does not
>>>>> deflect to one side when radially loaded. This is readily seen
>>>>> on any dished wheel.
>>>> Not true. Consider the case of a dished wheel built with no
>>>> tension in the non-drive spokes. Apply a radial load at a point
>>>> on the rim. Both the drive and non-drive spokes compress [assume
>>>> rim/spoke joint allows this]. The compression of the non-drive
>>>> spoke generates a side force, which must cause the rim to deflect
>>>> since the drive spokes were originally precisely vertical (normal
>>>> to rim).
>>> Jobst is correct. You are talking about a theoretical wheel, one
>>> not found on a bicycle which can be ridden.
>>> A bicycle wheel which can be used as a wheel cannot have zero
>>> tension anywhere, nor can it have drive side spokes normal to the
>>> rim since the drive side hub flange is offset from the centerline.
>> I didn't say that this was a practical wheel. This is a simple
>> model that illustrates that Jobst's (and beams's) assertion is
>> incorrect. A radial force applied to a wheel with an offset causes
>> (in general) a small lateral deflection. Some months ago I
>> computed the ratio and posted it here, but I don't really feel like
>> digging it up just now.
> Here's the result I was referring to (from "Spoke Tension Question",
> Jan 7 2006. x/y is the linearized ratio of vertical to lateral
> deflection for an applied radial load.
> /x1 x2 \
>
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Date: 26 Jun 2007 04:46:55
From: Luns Tee
Subject: Re: Mavic introduces wheel with compression spokes
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In article <46807202$0$14128$742ec2ed@news.sonic.net >,
<jobst.brandt@stanfordalumni.org > wrote:
>I think you can simplify this by hanging a weight on two unequal
>length lines (rope or wire), each of which is attached to an identical
>spring scale that gives elasticity as a spoke has and shows what
>forces are at work. As you increase or decrease the supported weight
>you will see no lateral position change.
Consider a related experiment: moving the weight vertically
by a small distance, restraining it against lateral motion, and see
what happens. The lengths of the two lines will change by that
distance times the cosines of their angles to vertical. Assuming the
same spring constant for both lines, the change in tensions will also
be proportional to the cosines. The lateral component of these tension
changes is just the sine of the lines' angles times the tension changes.
For the angles present in a wheel, the cosines are effectively
1, while the sines are on the order of 2:1. The lateral component of
the change in force from the two sides does not balance, being at about
this 2:1 ratio. The difference is supported by whatever lateral
restraint held the motion vertical. Without that restraint, the
vertex moves laterally.
The above assumed the the same spring constant from both lines:
choosing appropriately different spring constants can eliminate the
lateral motion. This is accomplished with thinner spokes on the
non-drive side, with spoke sectional areas in the same ratio as the
flange to centre-plane spacing. When this is the case, the strain
experienced by both spokes will be the same.
-Luns
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Date: 01 Jul 2007 00:45:53
From: Luns Tee
Subject: Re: Mavic introduces wheel with compression spokes
|
In article <f5q5nv$4tp$1@agate.berkeley.edu >,
Luns Tee <luns@mochi.EECS.Berkeley.EDU > wrote:
> Consider a related experiment: moving the weight vertically
>by a small distance, restraining it against lateral motion, and see
>what happens. The lengths of the two lines will change by that
>distance times the cosines of their angles to vertical. Assuming the
>same spring constant for both lines, the change in tensions will also
>be proportional to the cosines. The lateral component of these tension
>changes is just the sine of the lines' angles times the tension changes.
>
> For the angles present in a wheel, the cosines are effectively
>1, while the sines are on the order of 2:1. The lateral component of
>the change in force from the two sides does not balance, being at about
>this 2:1 ratio. The difference is supported by whatever lateral
>restraint held the motion vertical. Without that restraint, the
>vertex moves laterally.
It occurs to me that the same reasnong applies to purely lateral
loads. The lengths (hence tensions) now change with the sines relative
to vertical, while the vertical components of the tensions change with
the cosines. A purely lateral motion of the rim results in an
imbalance of vertical forces. If this imbalance isn't restrained - and
the imbalance is of the same sin*cos as before - then there must be a
vertical motion associated with the lateral load, just as we have a
horizontal motion resulting from vertical loads.
-Luns
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Date: 25 Jun 2007 18:24:54
From: Joe Riel
Subject: Re: Mavic introduces wheel with compression spokes
|
jobst.brandt@stanfordalumni.org writes:
> Joe Riel writes:
>
>>> Consider the spoke/hub configuration, a triangle, with the hub as
>>> its base. The tension ratio is the same as its loading ratio.
>>> That is to say, as the rim is pressed radially toward the hub, the
>>> length of the left and right elements change inversely with the
>>> tangent of the angle, (the same as the tension ratio of spokes,
>>> left and right). The rim does not deflect to one side when
>>> radially loaded. This is readily seen on any dished wheel.
>
>> Not true. Consider the case of a dished wheel built with no tension
>> in the non-drive spokes. Apply a radial load at a point on the rim.
>> Both the drive and non-drive spokes compress [assume rim/spoke joint
>> allows this]. The compression of the non-drive spoke generates a
>> side force, which must cause the rim to deflect since the drive
>> spokes were originally precisely vertical (normal to rim).
>
> How do you make a one sided wheel carry a load? Why put spokes in the
> left side at all, since the wheel is centered on the right
> flange... but not true. If you ever try such a wheel, with any
> tension capable of carrying a load, you will notice that it cannot be
> trued.
>
> I believe your hypothetical case has no bearing on the question of
> load support by a dished wheel. Once spokes become slack, the wheel
> is no longer whole. It essentially has missing spokes.
That was a theoretical example. It disproves the assertion that a
radial force applied to an offset wheel causes a pure radial
deflection. There is an accompanying lateral deflection. The ratio
of lateral to radial deflection can be computed (and I believe that I
posted it here some time ago).
--
Joe Riel
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Date: 25 Jun 2007 22:21:08
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
Joe Riel wrote:
> jobst.brandt@stanfordalumni.org writes:
>
>> Joe Riel writes:
>>
>>>> Consider the spoke/hub configuration, a triangle, with the hub as
>>>> its base. The tension ratio is the same as its loading ratio.
>>>> That is to say, as the rim is pressed radially toward the hub, the
>>>> length of the left and right elements change inversely with the
>>>> tangent of the angle, (the same as the tension ratio of spokes,
>>>> left and right). The rim does not deflect to one side when
>>>> radially loaded. This is readily seen on any dished wheel.
>>> Not true. Consider the case of a dished wheel built with no tension
>>> in the non-drive spokes. Apply a radial load at a point on the rim.
>>> Both the drive and non-drive spokes compress [assume rim/spoke joint
>>> allows this]. The compression of the non-drive spoke generates a
>>> side force, which must cause the rim to deflect since the drive
>>> spokes were originally precisely vertical (normal to rim).
>> How do you make a one sided wheel carry a load? Why put spokes in the
>> left side at all, since the wheel is centered on the right
>> flange... but not true. If you ever try such a wheel, with any
>> tension capable of carrying a load, you will notice that it cannot be
>> trued.
>>
>> I believe your hypothetical case has no bearing on the question of
>> load support by a dished wheel. Once spokes become slack, the wheel
>> is no longer whole. It essentially has missing spokes.
>
> That was a theoretical example. It disproves the assertion that a
> radial force applied to an offset wheel causes a pure radial
> deflection. There is an accompanying lateral deflection. The ratio
> of lateral to radial deflection can be computed (and I believe that I
> posted it here some time ago).
>
you're right, but the displacement is minimal is it not? in which case,
the simple model that does not account for it is sufficient for a very
good approximation.
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Date: 25 Jun 2007 18:21:53
From: Joe Riel
Subject: Re: Mavic introduces wheel with compression spokes
|
Ted Bennett <tedbennett@earthlink.net > writes:
> Joe Riel wrote:
>
>> jobst.brandt@stanfordalumni.org writes:
>>
>> > Consider the spoke/hub configuration, a triangle, with the hub as its
>> > base. The tension ratio is the same as its loading ratio. That is to
>> > say, as the rim is pressed radially toward the hub, the length of the
>> > left and right elements change inversely with the tangent of the
>> > angle, (the same as the tension ratio of spokes, left and right). The
>> > rim does not deflect to one side when radially loaded. This is
>> > readily seen on any dished wheel.
>>
>> Not true. Consider the case of a dished wheel built with no tension
>> in the non-drive spokes. Apply a radial load at a point on the rim.
>> Both the drive and non-drive spokes compress [assume rim/spoke joint
>> allows this]. The compression of the non-drive spoke generates a side
>> force, which must cause the rim to deflect since the drive spokes were
>> originally precisely vertical (normal to rim).
>
> Jobst is correct. You are talking about a theoretical wheel, one not
> found on a bicycle which can be ridden.
>
> A bicycle wheel which can be used as a wheel cannot have zero tension
> anywhere, nor can it have drive side spokes normal to the rim since the
> drive side hub flange is offset from the centerline.
I didn't say that this was a practical wheel. This is a simple model
that illustrates that Jobst's (and beams's) assertion is incorrect. A
radial force applied to a wheel with an offset causes (in general) a
small lateral deflection. Some months ago I computed the ratio and
posted it here, but I don't really feel like digging it up just now.
--
Joe Riel
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Date: 26 Jun 2007 01:45:42
From:
Subject: Re: Mavic introduces wheel with compression spokes
|
Joe Riel writes:
>>>> Consider the spoke/hub configuration, a triangle, with the hub as its
>>>> base. The tension ratio is the same as its loading ratio. That is to
>>>> say, as the rim is pressed radially toward the hub, the length of the
>>>> left and right elements change inversely with the tangent of the
>>>> angle, (the same as the tension ratio of spokes, left and right). The
>>>> rim does not deflect to one side when radially loaded. This is
>>>> readily seen on any dished wheel.
>>> Not true. Consider the case of a dished wheel built with no tension
>>> in the non-drive spokes. Apply a radial load at a point on the rim.
>>> Both the drive and non-drive spokes compress [assume rim/spoke joint
>>> allows this]. The compression of the non-drive spoke generates a side
>>> force, which must cause the rim to deflect since the drive spokes were
>>> originally precisely vertical (normal to rim).
>> Jobst is correct. You are talking about a theoretical wheel, one not
>> found on a bicycle which can be ridden.
>> A bicycle wheel which can be used as a wheel cannot have zero tension
>> anywhere, nor can it have drive side spokes normal to the rim since the
>> drive side hub flange is offset from the centerline.
> I didn't say that this was a practical wheel. This is a simple model
> that illustrates that Jobst's (and beams's) assertion is incorrect. A
> radial force applied to a wheel with an offset causes (in general) a
> small lateral deflection. Some months ago I computed the ratio and
> posted it here, but I don't really feel like digging it up just now.
Well, you'll need to dig it up and explain why your analysis is
germane. Let Google help you. I don't recall a valid explanation of
a change in lateral position of a dished wheel under load, one in
which spokes are not slack.
Besides, it isn't hard to write a proof of why it isn't so as you see.
Jobst Brandt
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Date: 25 Jun 2007 12:34:20
From: Joe Riel
Subject: Re: Mavic introduces wheel with compression spokes
|
jobst.brandt@stanfordalumni.org writes:
> Consider the spoke/hub configuration, a triangle, with the hub as its
> base. The tension ratio is the same as its loading ratio. That is to
> say, as the rim is pressed radially toward the hub, the length of the
> left and right elements change inversely with the tangent of the
> angle, (the same as the tension ratio of spokes, left and right). The
> rim does not deflect to one side when radially loaded. This is
> readily seen on any dished wheel.
Not true. Consider the case of a dished wheel built with no tension
in the non-drive spokes. Apply a radial load at a point on the rim.
Both the drive and non-drive spokes compress [assume rim/spoke joint
allows this]. The compression of the non-drive spoke generates a side
force, which must cause the rim to deflect since the drive spokes were
originally precisely vertical (normal to rim).
--
Joe Riel
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Date: 26 Jun 2007 01:00:15
From:
Subject: Re: Mavic introduces wheel with compression spokes
|
Joe Riel writes:
>> Consider the spoke/hub configuration, a triangle, with the hub as
>> its base. The tension ratio is the same as its loading ratio.
>> That is to say, as the rim is pressed radially toward the hub, the
>> length of the left and right elements change inversely with the
>> tangent of the angle, (the same as the tension ratio of spokes,
>> left and right). The rim does not deflect to one side when
>> radially loaded. This is readily seen on any dished wheel.
> Not true. Consider the case of a dished wheel built with no tension
> in the non-drive spokes. Apply a radial load at a point on the rim.
> Both the drive and non-drive spokes compress [assume rim/spoke joint
> allows this]. The compression of the non-drive spoke generates a
> side force, which must cause the rim to deflect since the drive
> spokes were originally precisely vertical (normal to rim).
How do you make a one sided wheel carry a load? Why put spokes in the
left side at all, since the wheel is centered on the right
flange... but not true. If you ever try such a wheel, with any
tension capable of carrying a load, you will notice that it cannot be
trued.
I believe your hypothetical case has no bearing on the question of
load support by a dished wheel. Once spokes become slack, the wheel
is no longer whole. It essentially has missing spokes.
Jobst Brandt
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Date: 26 Jun 2007 00:41:07
From: Ted Bennett
Subject: Re: Mavic introduces wheel with compression spokes
|
Joe Riel wrote:
> jobst.brandt@stanfordalumni.org writes:
>
> > Consider the spoke/hub configuration, a triangle, with the hub as its
> > base. The tension ratio is the same as its loading ratio. That is to
> > say, as the rim is pressed radially toward the hub, the length of the
> > left and right elements change inversely with the tangent of the
> > angle, (the same as the tension ratio of spokes, left and right). The
> > rim does not deflect to one side when radially loaded. This is
> > readily seen on any dished wheel.
>
> Not true. Consider the case of a dished wheel built with no tension
> in the non-drive spokes. Apply a radial load at a point on the rim.
> Both the drive and non-drive spokes compress [assume rim/spoke joint
> allows this]. The compression of the non-drive spoke generates a side
> force, which must cause the rim to deflect since the drive spokes were
> originally precisely vertical (normal to rim).
Jobst is correct. You are talking about a theoretical wheel, one not
found on a bicycle which can be ridden.
A bicycle wheel which can be used as a wheel cannot have zero tension
anywhere, nor can it have drive side spokes normal to the rim since the
drive side hub flange is offset from the centerline.
Ted
--
Ted Bennett
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Date: 25 Jun 2007 14:18:10
From: Gary Young
Subject: Re: Mavic introduces wheel with compression spokes
|
On Mon, 25 Jun 2007 18:31:17 +0000, jobst.brandt wrote:
> Gary Young writes:
>
>>>>> where do you get that from? the geometry doesn't change, therefore the
>>>>> ratio doesn't change.
>
>>>> Let's say that the tension ratio is 2 to 1... NDS= 50kg, and DS=
>>>> 100kg. As you move the rim vertically, the change in tension will
>>>> be nearly the same, so when the NDS gets down to 10kg the DS will
>>>> be 60kg... so now the ratio is 6 to 1.
>
>>> doesn't work like that. if the ratio is 2:1 and drive side drops
>>> to 50kgf, nds will be 25kgf. if it drops to 0.001kgf ds, nds drops
>>> to 0.0005kgf. ratio is fixed by geometry. you'd have to change
>>> geometry to change ratio, not tension.
>
>> I think you're befuddling yourself with Zeno's paradox. If the
>> left- hand spoke can only take a load of X before going slack, while
>> the right-side spoke can take a load of 2X before going slack, then
>> the ratio will fail to hold as soon as the load reaches X. At that
>> point, the left-hand spoke will go slack while the right-side spoke
>> still has tension (in a normal wheel). In the new Mavic wheel, the
>> left side goes into compression while the right-hand side still has
>> tension. Note that this is only true of the spokes directly above
>> the contact patch; in most of the rest of the wheel, spokes on both
>> sides will still be in tension.
>
> Consider the spoke/hub configuration, a triangle, with the hub as its
> base. The tension ratio is the same as its loading ratio. That is to
> say, as the rim is pressed radially toward the hub, the length of the
> left and right elements change inversely with the tangent of the
> angle, (the same as the tension ratio of spokes, left and right). The
> rim does not deflect to one side when radially loaded. This is
> readily seen on any dished wheel.
>
Since your analysis relies entirely on geometry and the ratio of loading
and tension, I take it I was also incorrect in thinking that having spokes
of different materials would make a difference in the way this wheel would
behave when subjected to radial loads.
> It seems the Mavic story is incorrect because they are shown testing
> an unloaded wheel with a side load, something that does not occur in
> normal use.
>
> Jobst Brandt
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Date: 25 Jun 2007 12:24:47
From: Gary Young
Subject: Re: Mavic introduces wheel with compression spokes
|
On Mon, 25 Jun 2007 07:46:00 -0700, Joe Riel wrote:
> jim beam <spamvortex@bad.example.net> writes:
>
>> garyyoung3@gmail.com wrote:
>>> On Jun 25, 2:28 am, garyyou...@gmail.com wrote: <snip>
>>>
>>>> Exactly. It sounds to me as if Mavic has designed this wheel with
>>>> tensions low enough that the right-side spokes routinely go slack
>>>> with typical loads as they pass the contact patch. And consequently
>>>> the left-side spokes lose all tension and compress as they pass the
>>>> contact patch.
>>>>
>>>>
>>> Nah. I'm going to backtrack. It's only necessary that a typical load
>>> make the left-side spokes go slack as they pass the contact patch. At
>>> that point, they're free to go into compression even if the left-hand
>>> spokes still have some tension.
>>>
>> impossible. tension ratio has to remain unless laterally loaded. see
>> above.
>
> That's not immediately clear. Even with a pure radial load, the rim has
> to deflect sideways (because of the unequal spoke angle constraints).
> That locally bends the rim, which is equivalent to a lateral force, more
> or less. It seems a reasonable approximation, but... Did Damon
> Richard measure the tension change with a pure radial load in an offset
> wheel?
>
>
Maybe I'm missing something, but it seems to me that there has to be
sideways deflection if the spokes on either side of the wheel are of the
same flexibility or are equally free to move laterally at the rim and hub.
But the carbon-fiber spokes on the Mavic wheel appear to be far more
constrained in their lateral movement at the hub and the material itself
is less flexible. See for instance the first photograph on this page:
http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html
Judging from the way the head of the nipple is flat (not radiused) and is
pressed up against the inside of the hub by the round ring, I'd say the
carbon-fiber spokes aren't meant to have any lateral play at the hub.
It's true that the tensioned spokes on the right side will tend to bend
the carbon-fiber spokes rightward, but they will bend much less than
conventional spokes would.
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Date: 25 Jun 2007 08:48:06
From: Ron Ruff
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 25, 7:06 am, jim beam <spamvor...@bad.example.net > wrote:
> not possible. ratio is fixed. if x is positive, "2x" is positive. if
> x is negative, 2x is negative. slack is when tension is zero. if x =
> zero, 2x is zero - for all values of zero! can't have one value
> positive and the other negative if still connected.
In a normal wheel with a 2:1 tension ration in the back (unstressed)
and the same spokes on both sides, if a vertical load is applied the
NDS spokes at the bottom of the wheel will go slack *before* the DS.
True or false? And if you still maintain that this is false, then
please explain why.
Also think about what happens if you take one spoke on a wheel and
loosen it completely, so that the local tension ratio is now say 0kg
to 100kg. This is quite common... and does not result in "impossible"
geometries.
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| | |
Date: 25 Jun 2007 22:22:10
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
Ron Ruff wrote:
> On Jun 25, 7:06 am, jim beam <spamvor...@bad.example.net> wrote:
>> not possible. ratio is fixed. if x is positive, "2x" is positive. if
>> x is negative, 2x is negative. slack is when tension is zero. if x =
>> zero, 2x is zero - for all values of zero! can't have one value
>> positive and the other negative if still connected.
>
> In a normal wheel with a 2:1 tension ration in the back (unstressed)
> and the same spokes on both sides, if a vertical load is applied the
> NDS spokes at the bottom of the wheel will go slack *before* the DS.
> True or false?
false. they both go to zero at the same time.
> And if you still maintain that this is false, then
> please explain why.
i already have. it's a fixed ratio. if y = 2x, you can't just go
changing the 2 - which is what you're trying to suggest.
>
> Also think about what happens if you take one spoke on a wheel and
> loosen it completely, so that the local tension ratio is now say 0kg
> to 100kg. This is quite common... and does not result in "impossible"
> geometries.
>
because tension increases on the neighboring same-side spokes /and/ the
rim displaces! if you want the rim to not be displaced, you have to
re-tension the spoke!
|
| |
Date: 25 Jun 2007 07:46:00
From: Joe Riel
Subject: Re: Mavic introduces wheel with compression spokes
|
jim beam <spamvortex@bad.example.net > writes:
> garyyoung3@gmail.com wrote:
>> On Jun 25, 2:28 am, garyyou...@gmail.com wrote:
>> <snip>
>>
>>> Exactly. It sounds to me as if Mavic has designed this wheel with
>>> tensions low enough that the right-side spokes routinely go slack with
>>> typical loads as they pass the contact patch. And consequently the
>>> left-side spokes lose all tension and compress as they pass the
>>> contact patch.
>>>
>>
>> Nah. I'm going to backtrack. It's only necessary that a typical load
>> make the left-side spokes go slack as they pass the contact patch. At
>> that point, they're free to go into compression even if the left-hand
>> spokes still have some tension.
>>
> impossible. tension ratio has to remain unless laterally loaded. see
> above.
That's not immediately clear. Even with a pure radial load, the rim
has to deflect sideways (because of the unequal spoke angle
constraints). That locally bends the rim, which is equivalent to a
lateral force, more or less. It seems a reasonable approximation,
but... Did Damon Richard measure the tension change with a pure
radial load in an offset wheel?
--
Joe Riel
|
| | |
Date: 25 Jun 2007 11:33:01
From:
Subject: Re: Mavic introduces wheel with compression spokes
|
On Mon, 25 Jun 2007 07:46:00 -0700, Joe Riel <joer@san.rr.com > wrote:
>jim beam <spamvortex@bad.example.net> writes:
>
>> garyyoung3@gmail.com wrote:
>>> On Jun 25, 2:28 am, garyyou...@gmail.com wrote:
>>> <snip>
>>>
>>>> Exactly. It sounds to me as if Mavic has designed this wheel with
>>>> tensions low enough that the right-side spokes routinely go slack with
>>>> typical loads as they pass the contact patch. And consequently the
>>>> left-side spokes lose all tension and compress as they pass the
>>>> contact patch.
>>>>
>>>
>>> Nah. I'm going to backtrack. It's only necessary that a typical load
>>> make the left-side spokes go slack as they pass the contact patch. At
>>> that point, they're free to go into compression even if the left-hand
>>> spokes still have some tension.
>>>
>> impossible. tension ratio has to remain unless laterally loaded. see
>> above.
>
>That's not immediately clear. Even with a pure radial load, the rim
>has to deflect sideways (because of the unequal spoke angle
>constraints). That locally bends the rim, which is equivalent to a
>lateral force, more or less. It seems a reasonable approximation,
>but... Did Damon Richard measure the tension change with a pure
>radial load in an offset wheel?
Dear Joe,
http://www.sheldonbrown.com/rinard/wheel/index.htm
Cheers,
Carl Fogel
|
| |
Date: 25 Jun 2007 06:56:59
From:
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 23, 9:19 am, jim beam <spamvor...@bad.example.net > wrote:
> Ron Ruff wrote:
> > On Jun 22, 10:25 pm, jim beam <spamvor...@bad.example.net> wrote:
> >> where do you get that from? the geometry doesn't change, therefore the
> >> ratio doesn't change.
>
> > Let's say that the tension ratio is 2 to 1... NDS= 50kg, and DS=
> > 100kg. As you move the rim vertically, the change in tension will be
> > nearly the same, so when the NDS gets down to 10kg the DS will be
> > 60kg... so now the ratio is 6 to 1.
>
> doesn't work like that. if the ratio is 2:1 and drive side drops to
> 50kgf, nds will be 25kgf. if it drops to 0.001kgf ds, nds drops to
> 0.0005kgf. ratio is fixed by geometry. you'd have to change geometry
> to change ratio, not tension.
I think you're befuddling yourself with zeno's paradox. If the left-
hand spoke can only take a load of X before going slack, while the
right-side spoke can take a load of 2X before going slack, then the
ratio will fail to hold as soon as the load reaches X. At that point,
the left-hand spoke will go slack while the right-side spoke still has
tension (in a normal wheel). In the new Mavic wheel, the left side
goes into compression while the right-hand side still has tension.
Note that this is only true of the spokes directly above the contact
patch; in most of the rest of the wheel, spokes on both sides will
still be in tension.
>
> > In the real world the rest of the
> > wheel will be involved, and also the rim will move sideways... and the
> > same thing will happen with compression spokes.
>
> said that before: lateral loading is the only way you can observe a
> different tension ratio.
>
>
>
> >> again, where does all this stuff come from? download damon rinard's
> >> spoke calc spreadsheet.http://sheldonbrown.com/rinard/spocalc.xls
> >> the tension ratio is in there. you'd have to have some pretty loopy hub
> >> flange spacing to get only 20%.
>
> > Loopy maybe, but easy to do. Make the DS spacing 10mm (instead of the
> > typical 18mm) and the NDS spacing 50mm and there you have it.
>
> right, but it's not 10mm:50mm and it's not variable!
|
| | |
Date: 26 Jun 2007 00:51:28
From: Michael Press
Subject: Re: Mavic introduces wheel with compression spokes
|
In article
<1182754619.277225.27810@n2g2000hse.googlegroups.com >,
garyyoung3@gmail.com wrote:
> On Jun 23, 9:19 am, jim beam <spamvor...@bad.example.net> wrote:
> > Ron Ruff wrote:
> > > On Jun 22, 10:25 pm, jim beam <spamvor...@bad.example.net> wrote:
> > >> where do you get that from? the geometry doesn't change, therefore the
> > >> ratio doesn't change.
> >
> > > Let's say that the tension ratio is 2 to 1... NDS= 50kg, and DS=
> > > 100kg. As you move the rim vertically, the change in tension will be
> > > nearly the same, so when the NDS gets down to 10kg the DS will be
> > > 60kg... so now the ratio is 6 to 1.
> >
> > doesn't work like that. if the ratio is 2:1 and drive side drops to
> > 50kgf, nds will be 25kgf. if it drops to 0.001kgf ds, nds drops to
> > 0.0005kgf. ratio is fixed by geometry. you'd have to change geometry
> > to change ratio, not tension.
>
> I think you're befuddling yourself with zeno's paradox. If the left-
> hand spoke can only take a load of X before going slack, while the
> right-side spoke can take a load of 2X before going slack, then the
> ratio will fail to hold as soon as the load reaches X.
No. The lateral components of the forces applied to the
rim by the two spokes must balance. The two spokes
reach zero tension together. If the right hand spoke
has zero tension and the left hand spoke is under
tension the left hand spoke will pull the rim leftward.
--
Michael Press
|
| | |
Date: 25 Jun 2007 18:31:17
From:
Subject: Re: Mavic introduces wheel with compression spokes
|
Gary Young writes:
>>>> where do you get that from? the geometry doesn't change, therefore the
>>>> ratio doesn't change.
>>> Let's say that the tension ratio is 2 to 1... NDS= 50kg, and DS=
>>> 100kg. As you move the rim vertically, the change in tension will
>>> be nearly the same, so when the NDS gets down to 10kg the DS will
>>> be 60kg... so now the ratio is 6 to 1.
>> doesn't work like that. if the ratio is 2:1 and drive side drops
>> to 50kgf, nds will be 25kgf. if it drops to 0.001kgf ds, nds drops
>> to 0.0005kgf. ratio is fixed by geometry. you'd have to change
>> geometry to change ratio, not tension.
> I think you're befuddling yourself with Zeno's paradox. If the
> left- hand spoke can only take a load of X before going slack, while
> the right-side spoke can take a load of 2X before going slack, then
> the ratio will fail to hold as soon as the load reaches X. At that
> point, the left-hand spoke will go slack while the right-side spoke
> still has tension (in a normal wheel). In the new Mavic wheel, the
> left side goes into compression while the right-hand side still has
> tension. Note that this is only true of the spokes directly above
> the contact patch; in most of the rest of the wheel, spokes on both
> sides will still be in tension.
Consider the spoke/hub configuration, a triangle, with the hub as its
base. The tension ratio is the same as its loading ratio. That is to
say, as the rim is pressed radially toward the hub, the length of the
left and right elements change inversely with the tangent of the
angle, (the same as the tension ratio of spokes, left and right). The
rim does not deflect to one side when radially loaded. This is
readily seen on any dished wheel.
It seems the Mavic story is incorrect because they are shown testing
an unloaded wheel with a side load, something that does not occur in
normal use.
Jobst Brandt
|
| | |
Date: 25 Jun 2007 18:11:06
From:
Subject: Re: Mavic introduces wheel with compression spokes
|
Gary Young writes:
>>>> where do you get that from? the geometry doesn't change, therefore the
>>>> ratio doesn't change.
>>> Let's say that the tension ratio is 2 to 1... NDS= 50kg, and DS=
>>> 100kg. As you move the rim vertically, the change in tension will
>>> be nearly the same, so when the NDS gets down to 10kg the DS will
>>> be 60kg... so now the ratio is 6 to 1.
>> doesn't work like that. if the ratio is 2:1 and drive side drops
>> to 50kgf, nds will be 25kgf. if it drops to 0.001kgf ds, nds drops
>> to 0.0005kgf. ratio is fixed by geometry. you'd have to change
>> geometry to change ratio, not tension.
> I think you're befuddling yourself with Zeno's paradox. If the
> left- hand spoke can only take a load of X before going slack, while
> the right-side spoke can take a load of 2X before going slack, then
> the ratio will fail to hold as soon as the load reaches X. At that
> point, the left-hand spoke will go slack while the right-side spoke
> still has tension (in a normal wheel). In the new Mavic wheel, the
> left side goes into compression while the right-hand side still has
> tension. Note that this is only true of the spokes directly above
> the contact patch; in most of the rest of the wheel, spokes on both
> sides will still be in tension.
Consider the spoke/hub configuration, a triangle, with the hub as its
base. The tension ratio is the same as its loading ration. That is
to say, as the rim is pressed radially toward the hub, the length of
the left and right elements change inversely with the tangent of the
angle, (the same as the tension ratio of spokes, left and right). The
rim does not deflect to one side when radially loaded. This is
readily seen on any dished wheel.
It seems the Mavic story is incorrect because they are shown testing
an unloaded wheel with a side load, something that does not occur in
normal use.
Jobst Brandt
|
| | |
Date: 25 Jun 2007 06:06:29
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
garyyoung3@gmail.com wrote:
> On Jun 23, 9:19 am, jim beam <spamvor...@bad.example.net> wrote:
>> Ron Ruff wrote:
>>> On Jun 22, 10:25 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>> where do you get that from? the geometry doesn't change, therefore the
>>>> ratio doesn't change.
>>> Let's say that the tension ratio is 2 to 1... NDS= 50kg, and DS=
>>> 100kg. As you move the rim vertically, the change in tension will be
>>> nearly the same, so when the NDS gets down to 10kg the DS will be
>>> 60kg... so now the ratio is 6 to 1.
>> doesn't work like that. if the ratio is 2:1 and drive side drops to
>> 50kgf, nds will be 25kgf. if it drops to 0.001kgf ds, nds drops to
>> 0.0005kgf. ratio is fixed by geometry. you'd have to change geometry
>> to change ratio, not tension.
>
> I think you're befuddling yourself with zeno's paradox. If the left-
> hand spoke can only take a load of X before going slack, while the
> right-side spoke can take a load of 2X before going slack, then the
> ratio will fail to hold as soon as the load reaches X.
not possible. ratio is fixed. if x is positive, "2x" is positive. if
x is negative, 2x is negative. slack is when tension is zero. if x =
zero, 2x is zero - for all values of zero! can't have one value
positive and the other negative if still connected.
> At that point,
> the left-hand spoke will go slack while the right-side spoke still has
> tension (in a normal wheel). In the new Mavic wheel, the left side
> goes into compression while the right-hand side still has tension.
> Note that this is only true of the spokes directly above the contact
> patch; in most of the rest of the wheel, spokes on both sides will
> still be in tension.
rubbish.
>
>
>>> In the real world the rest of the
>>> wheel will be involved, and also the rim will move sideways... and the
>>> same thing will happen with compression spokes.
>> said that before: lateral loading is the only way you can observe a
>> different tension ratio.
>>
>>
>>
>>>> again, where does all this stuff come from? download damon rinard's
>>>> spoke calc spreadsheet.http://sheldonbrown.com/rinard/spocalc.xls
>>>> the tension ratio is in there. you'd have to have some pretty loopy hub
>>>> flange spacing to get only 20%.
>>> Loopy maybe, but easy to do. Make the DS spacing 10mm (instead of the
>>> typical 18mm) and the NDS spacing 50mm and there you have it.
>> right, but it's not 10mm:50mm and it's not variable!
>
>
|
| |
Date: 25 Jun 2007 06:42:03
From:
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 25, 2:28 am, garyyou...@gmail.com wrote:
<snip >
> Exactly. It sounds to me as if Mavic has designed this wheel with
> tensions low enough that the right-side spokes routinely go slack with
> typical loads as they pass the contact patch. And consequently the
> left-side spokes lose all tension and compress as they pass the
> contact patch.
>
Nah. I'm going to backtrack. It's only necessary that a typical load
make the left-side spokes go slack as they pass the contact patch. At
that point, they're free to go into compression even if the left-hand
spokes still have some tension.
|
| | |
Date: 25 Jun 2007 06:07:05
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
garyyoung3@gmail.com wrote:
> On Jun 25, 2:28 am, garyyou...@gmail.com wrote:
> <snip>
>
>> Exactly. It sounds to me as if Mavic has designed this wheel with
>> tensions low enough that the right-side spokes routinely go slack with
>> typical loads as they pass the contact patch. And consequently the
>> left-side spokes lose all tension and compress as they pass the
>> contact patch.
>>
>
> Nah. I'm going to backtrack. It's only necessary that a typical load
> make the left-side spokes go slack as they pass the contact patch. At
> that point, they're free to go into compression even if the left-hand
> spokes still have some tension.
>
impossible. tension ratio has to remain unless laterally loaded. see
above.
|
| |
Date: 25 Jun 2007 06:28:14
From:
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 22, 9:59 pm, jim beam <spamvor...@bad.example.net > wrote:
> Gary Young wrote:
> > On Fri, 22 Jun 2007 17:28:48 +0100, Kinky Cowboy wrote:
>
> >> On Thu, 21 Jun 2007 21:34:22 -0700, jim beam
> >> <spamvor...@bad.example.net> wrote:
>
> >>> steve wrote:
> >>>> On Jun 21, 12:04 am, jim beam <spamvor...@bad.example.net> wrote:
> >>>>> steve wrote:
> >>>>>> On Jun 20, 8:51 am, jim beam <spamvor...@bad.example.net> wrote:
> >>>>>>> Gary Young wrote:
> >>>>>>>> Another blog posting on the wheel:
> >>>>>>>>http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html
> >>>>>>>> The description seems to me to be hopelessly confused, but there is a
> >>>>>>>> photograph showing how the carbon-fiber spokes connect to the hub.
> >>>>>>> well /this/http://rodale.typepad.com/.shared/image.html?/photos/uncategorized/20...
> >>>>>>> sure isn't a compression fitting!
> >>>>>> According towww.cyclingnews.comthecarbon spokes are in tension but
> >>>>>> are designed to handle compressive loads as well.
> >>>>> that's what the journalists write, but it's clearly not possible from
> >>>>> that picture.
>
> >>>>> Mavic has an end cap that presses into the end of the hub to prevent the spokes from being able to move vertically and allow them to take compressive loads. This site describes it a bit more elequently http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html.
> >>>> Steve Sauter
>
> >>> ok, thanks for that. but you're still not going to get compression on
> >>> one side of the rear and tension on the other.
> >> Not on an unloaded wheel. Add some side load from the road and all
> >> bets are off.
> >> Kinky Cowboy*
>
> >> *Batteries not included
> >> May contain traces of nuts
> >> Your milage may vary
>
> first off, kinky raises the only situation in which this could be
> possible. 10 points!
>
> > If the left side spokes are lightly tensioned, then they may go into
> > compression as they pass the contact patch. Only a few spokes would be in
> > compression. Wouldn't the remaining spokes in tension be enough to ensure
> > the structural integrity of the wheel? (At least when the wheel doesn't
> > encounter large lateral loads, since the low tension means a weak wheel.)
> > Mind you, I'm not trying to say that this is a good idea.
>
> not possible from radial loading without the drive side spokes going
> slack.
Exactly. It sounds to me as if Mavic has designed this wheel with
tensions low enough that the right-side spokes routinely go slack with
typical loads as they pass the contact patch. And consequently the
left-side spokes lose all tension and compress as they pass the
contact patch.
> tension ratio is a matter of geometry. if the ratio is 50%,
> it's 50% and can't change regardless of tension magnitude - if one side
> goes into compression, the other does too. and you can't compress those
> aluminum spokes.
|
| |
Date: 24 Jun 2007 22:31:48
From: PiledHIgher
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 25, 2:40 pm, "Kerry Montgomery" <kamon...@teleport.com > wrote:
>
> I'd much rather my WRX didn't have the plastic festoons, but it'd cost a
> bunch at the body shop to clean it up.
But then nobody would know it wasn't the base level Impreza that costs
half as much!
|
| |
Date: 24 Jun 2007 05:50:52
From: Johnny Sunset
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 23, 8:04 pm, Chalo Colina wrote:
> goo...@grafixbyjorj.net wrote:
>
> > It may be true to it's purpose, but paying $400-$1000 (yep, it's a
> > grand if you take the SRAM 7-speed and 700c wheels options) is as much
> > of a conceit as buying Ksyrium ESs "Just like the pros ride" even
> > though a $200 shimano wheel is better. The modern, not already rusty
> > before you get it, low maintenance Trek Lime Lite is only $500
>
> A lot of the direct ancestors of the Eastman Roadster are still on the
> road after more than half a century of real transportation duty. You
> think the Lime could do that? I don't.
>
> Besides, you just compared the price of a 7-speed bike with handbuilt
> upgraded wheels to that of a 3-speed bike with factory wheels. Like
> for like, I think it's easy to make the case that the Eastman is a
> better value. It's the same as the way that a 1982 Checker Marathon
> with all its "conceit" represented a much better value than a 1982 GM
> car of the same price. The Marathon is probably still kickin' and
> still stylish. The Seville? Long gone to the smelter, and not a
> moment too soon.
I see a lot of late 70's and early 80's cars in "da hood". Most are in
a condition where they would not pass safety and emissions
inspections, so they are driven without being registered.
--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful
|
| |
Date: 24 Jun 2007 05:02:26
From: Qui si parla Campagnolo
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 20, 9:07 am, jobst.bra...@stanfordalumni.org wrote:
> Steve Sauter writes:
>
> http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html
>
> >>> The description seems to me to be hopelessly confused, but there
> >>> is a photograph showing how the carbon-fiber spokes connect to the
> >>> hub.
> >> well /this/
>
> http://tinyurl.com/2m59r9
>
> >> sure isn't a compression fitting!
> > According towww.cyclingnews.comthe carbon spokes are in tension
> > but are designed to handle compressive loads as well. This allows
> > them to make a wheel with lower spoke tension thus a lighter rim
> > since it doesn't have to handle as much stress from the spokes.
> > Mavic has also finally given in to the asymmetric rim design for
> > there new wheels in order to help balance spoke tension. The reason
> > for the aluminum spokes on the drive side in the rear wheel is so
> > that they could use thin bladed spokes and thus place them as far
> > away from the center of the hub as possible. It looks like the
> > front wheel uses 18 spokes and the rear uses 24.
> > It sounds like a decent racing wheel to me but I am a bit skeptical
> > about how it will hold up for the general public.
>
> I don't understand what the difference between racing and other
> bicycling has for wheels. What is it a wheel must do in a race that
> is different from non-race riding. I seem to see differences implied
> that one is a greater stress than the other but the more stressful one
> changes depending on what point is being put forth.
>
> From what I see cruising up and down the avenue here, the all look
> like racing wheels, some costing as much as $4000 a pair, according to
> our local bicycle shops.
>
> Jobst Brandt
People also buy plastic festooned Subaru WRXs..and imagine themselves
in the wilds of Austria, stage 3 of the World Rally
Chmpionships...while going down to 7-11 for a slurpy...
|
| | |
Date: 25 Jun 2007 04:40:51
From: Kerry Montgomery
Subject: Re: Mavic introduces wheel with compression spokes
|
"Qui si parla Campagnolo" <peter@vecchios.com > wrote in message
news:1182686546.215085.94510@x35g2000prf.googlegroups.com...
> On Jun 20, 9:07 am, jobst.bra...@stanfordalumni.org wrote:
>> Steve Sauter writes:
>>
>> http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html
>>
>> >>> The description seems to me to be hopelessly confused, but there
>> >>> is a photograph showing how the carbon-fiber spokes connect to the
>> >>> hub.
>> >> well /this/
>>
>> http://tinyurl.com/2m59r9
>>
>> >> sure isn't a compression fitting!
>> > According towww.cyclingnews.comthe carbon spokes are in tension
>> > but are designed to handle compressive loads as well. This allows
>> > them to make a wheel with lower spoke tension thus a lighter rim
>> > since it doesn't have to handle as much stress from the spokes.
>> > Mavic has also finally given in to the asymmetric rim design for
>> > there new wheels in order to help balance spoke tension. The reason
>> > for the aluminum spokes on the drive side in the rear wheel is so
>> > that they could use thin bladed spokes and thus place them as far
>> > away from the center of the hub as possible. It looks like the
>> > front wheel uses 18 spokes and the rear uses 24.
>> > It sounds like a decent racing wheel to me but I am a bit skeptical
>> > about how it will hold up for the general public.
>>
>> I don't understand what the difference between racing and other
>> bicycling has for wheels. What is it a wheel must do in a race that
>> is different from non-race riding. I seem to see differences implied
>> that one is a greater stress than the other but the more stressful one
>> changes depending on what point is being put forth.
>>
>> From what I see cruising up and down the avenue here, the all look
>> like racing wheels, some costing as much as $4000 a pair, according to
>> our local bicycle shops.
>>
>> Jobst Brandt
>
> People also buy plastic festooned Subaru WRXs..and imagine themselves
> in the wilds of Austria, stage 3 of the World Rally
> Chmpionships...while going down to 7-11 for a slurpy...
>
I'd much rather my WRX didn't have the plastic festoons, but it'd cost a
bunch at the body shop to clean it up.
Oh, there's no Austrian round of the WRC, so my imagination leans toward
things Swedish or Italian :-)
Kerry
|
| |
Date: 24 Jun 2007 02:46:44
From: Chalo
Subject: Re: Eastman Roadster (was: Mavic introduces wheel with compression spokes)
|
Johnny Sunset wrote:
>
> Bill Sornson wrote:
> >
> > $750 for a Brooks Swallow? Hmmm.
>
> For $750 she better..., oh never mind, family newsgroup.
>
> B. Sornson appears to be referring to this: <http://www.yellowjersey.org/swallow7.html>.
That is just ridiculous-- half a saddle for ten times the price of a
whole one.
It's as outlandish in its excess as a $550 unpadded plastic chip:
http://fairwheelbikes.com/index.php?main_page=product_info&cPath=19&products_id=256
But I bet the half-a-Brooks is still a lot better to sit on.
Chalo
|
| |
Date: 24 Jun 2007 01:04:50
From: Chalo
Subject: Re: Mavic introduces wheel with compression spokes
|
goo...@grafixbyjorj.net wrote:
>
> It may be true to it's purpose, but paying $400-$1000 (yep, it's a
> grand if you take the SRAM 7-speed and 700c wheels options) is as much
> of a conceit as buying Ksyrium ESs "Just like the pros ride" even
> though a $200 shimano wheel is better. The modern, not already rusty
> before you get it, low maintenance Trek Lime Lite is only $500
A lot of the direct ancestors of the Eastman Roadster are still on the
road after more than half a century of real transportation duty. You
think the Lime could do that? I don't.
Besides, you just compared the price of a 7-speed bike with handbuilt
upgraded wheels to that of a 3-speed bike with factory wheels. Like
for like, I think it's easy to make the case that the Eastman is a
better value. It's the same as the way that a 1982 Checker Marathon
with all its "conceit" represented a much better value than a 1982 GM
car of the same price. The Marathon is probably still kickin' and
still stylish. The Seville? Long gone to the smelter, and not a
moment too soon.
Chalo
|
| | |
Date: 24 Jun 2007 12:30:42
From: Kinky Cowboy
Subject: Re: Mavic introduces wheel with compression spokes
|
On Sun, 24 Jun 2007 01:04:50 -0000, Chalo <chalo.colina@gmail.com >
wrote:
>goo...@grafixbyjorj.net wrote:
>>
>> It may be true to it's purpose, but paying $400-$1000 (yep, it's a
>> grand if you take the SRAM 7-speed and 700c wheels options) is as much
>> of a conceit as buying Ksyrium ESs "Just like the pros ride" even
>> though a $200 shimano wheel is better. The modern, not already rusty
>> before you get it, low maintenance Trek Lime Lite is only $500
>
>A lot of the direct ancestors of the Eastman Roadster are still on the
>road after more than half a century of real transportation duty. You
>think the Lime could do that? I don't.
>
>Besides, you just compared the price of a 7-speed bike with handbuilt
>upgraded wheels to that of a 3-speed bike with factory wheels. Like
>for like, I think it's easy to make the case that the Eastman is a
>better value.
The three speed Eastman is $550, so you've got $50 worth of wheel
tweaking to spend on the Lime Lite to make a like-for-like comparison
on price. Or maybe you'd spend the $50 on some mudguards. Whatever. My
point was not that the Lime Lite is the perfect utility bicycle; it's
that, with modern manufacturing methods, the Taiwanese could build a
single speed steel framed utility bike for way less than $400, and do
it much better than the Indians. If there was a market for a cheap old
fashioned bike, the Taiwanese would be making them and selling through
supermarkets for <$150. As it stands, buyers of old fashioned bikes
are just another kind of middle class poseur so Eastman, Pashley ($900
3-speed) and Batavus ($650 single speed) stay in business.
Kinky Cowboy*
*Batteries not included
May contain traces of nuts
Your milage may vary
|
| |
Date: 23 Jun 2007 15:32:50
From: Johnny Sunset
Subject: Re: Eastman Roadster (was: Mavic introduces wheel with compression spokes)
|
On Jun 23, 4:19 pm, Bill Sornson wrote:
> Johnny Sunset wrote:
> > On Jun 23, 8:48 am, "jim beam" (who?) anonymously wrote:
>
> >> arise komrades of ameristan! free yourselves of your kapitalist
> >> shackles! invest thusly in your
> >> transportation:http://www.yellowjersey.org/EASTMAN.HTML
>
> > Andrew Muzi must be brave, quick or both:
> > <http://www.yellowjersey.org/EASTMAN6.JPG> - note the Metro bus
> > bearing down. My experience with Madison Metro [1] drivers is that
> > there is a decent percentage who would just as well run someone over
> > as brake or steer out of the way. However, the Eastman Roadster is
> > likely solid enough to survive a collision with the mopeds that
> > plague downtown Madison (when school is in session) without real
> > damage.
>
> > [1] <http://www.ci.madison.wi.us/metro/>.
>
> $750 for a Brooks Swallow? Hmmm.
For $750 she better..., oh never mind, family newsgroup.
B. Sornson appears to be referring to this: <http://
www.yellowjersey.org/swallow7.html >.
--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful
|
| | |
Date: 23 Jun 2007 17:37:37
From: Bill Sornson
Subject: Re: Eastman Roadster (was: Mavic introduces wheel with compression spokes)
|
Johnny Sunset wrote:
> On Jun 23, 4:19 pm, Bill Sornson wrote:
>> Johnny Sunset wrote:
>>> On Jun 23, 8:48 am, "jim beam" (who?) anonymously wrote:
>>
>>>> arise komrades of ameristan! free yourselves of your kapitalist
>>>> shackles! invest thusly in your
>>>> transportation:http://www.yellowjersey.org/EASTMAN.HTML
>>
>>> Andrew Muzi must be brave, quick or both:
>>> <http://www.yellowjersey.org/EASTMAN6.JPG> - note the Metro bus
>>> bearing down. My experience with Madison Metro [1] drivers is that
>>> there is a decent percentage who would just as well run someone over
>>> as brake or steer out of the way. However, the Eastman Roadster is
>>> likely solid enough to survive a collision with the mopeds that
>>> plague downtown Madison (when school is in session) without real
>>> damage.
>>
>>> [1] <http://www.ci.madison.wi.us/metro/>.
>>
>> $750 for a Brooks Swallow? Hmmm.
>
> For $750 she better..., oh never mind, family newsgroup.
Indeed.
> B. Sornson appears to be referring to this: <http://
> www.yellowjersey.org/swallow7.html>.
Indeed.
(Your link, above, was broken on my NR, taking me to a different YJ page
than intended. Saw the Swallow, Gulped at the price, Tasted a little bile,
and then pasted the remaining text to see the bus.)
Bill "slow afternoon, obviously" S.
|
| |
Date: 23 Jun 2007 14:39:52
From: Ozark Bicycle
Subject: Re: Eastman Roadster (was: Mavic introduces wheel with compression spokes)
|
On Jun 23, 4:19 pm, "Bill Sornson" <a...@ask.me > wrote:
> Johnny Sunset wrote:
> > On Jun 23, 8:48 am, "jim beam" (who?) anonymously wrote:
>
> >> arise komrades of ameristan! free yourselves of your kapitalist
> >> shackles! invest thusly in your
> >> transportation:http://www.yellowjersey.org/EASTMAN.HTML
>
> > Andrew Muzi must be brave, quick or both:
> > <http://www.yellowjersey.org/EASTMAN6.JPG> - note the Metro bus
> > bearing down. My experience with Madison Metro [1] drivers is that
> > there is a decent percentage who would just as well run someone over
> > as brake or steer out of the way. However, the Eastman Roadster is
> > likely solid enough to survive a collision with the mopeds that
> > plague downtown Madison (when school is in session) without real
> > damage.
>
> > [1] <http://www.ci.madison.wi.us/metro/>.
>
> $750 for a Brooks Swallow? Hmmm.-
Why spend less? ;-)
|
| |
Date: 23 Jun 2007 09:07:43
From: Johnny Sunset
Subject: Eastman Roadster (was: Mavic introduces wheel with compression spokes)
|
On Jun 23, 8:48 am, "jim beam" (who?) anonymously wrote:
>
> arise komrades of ameristan! free yourselves of your kapitalist
> shackles! invest thusly in your transportation:http://www.yellowjersey.org/EASTMAN.HTML
Andrew Muzi must be brave, quick or both: <http://www.yellowjersey.org/
EASTMAN6.JPG > - note the Metro bus bearing down. My experience with
Madison Metro [1] drivers is that there is a decent percentage who
would just as well run someone over as brake or steer out of the way.
However, the Eastman Roadster is likely solid enough to survive a
collision with the mopeds that plague downtown Madison (when school is
in session) without real damage.
[1] <http://www.ci.madison.wi.us/metro/ >.
--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful
|
| | |
Date: 24 Jun 2007 17:10:38
From: A Muzi
Subject: Re: Eastman Roadster
|
> On Jun 23, 8:48 am, "jim beam" (who?) anonymously wrote:
>> arise komrades of ameristan! free yourselves of your kapitalist
>> shackles! invest thusly in your transportation:http://www.yellowjersey.org/EASTMAN.HTML
Johnny Sunset wrote:
> Andrew Muzi must be brave, quick or both: <http://www.yellowjersey.org/
> EASTMAN6.JPG> - note the Metro bus bearing down. My experience with
> Madison Metro [1] drivers is that there is a decent percentage who
> would just as well run someone over as brake or steer out of the way.
> However, the Eastman Roadster is likely solid enough to survive a
> collision with the mopeds that plague downtown Madison (when school is
> in session) without real damage.
>
> [1] <http://www.ci.madison.wi.us/metro/>.
In theory, the guy's cushy union job would be at risk if he hit me, so I
provoke them mercilessly on my bike. So far no hits- which is more than
I can say for space-cadet cell phone users piloting room sized SUVs.
Simply walking in the street for a snapshot isn't risky, do it every day:
http://www.yellowjersey.org/daily.html
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | |
Date: 23 Jun 2007 14:19:44
From: Bill Sornson
Subject: Re: Eastman Roadster (was: Mavic introduces wheel with compression spokes)
|
Johnny Sunset wrote:
> On Jun 23, 8:48 am, "jim beam" (who?) anonymously wrote:
>>
>> arise komrades of ameristan! free yourselves of your kapitalist
>> shackles! invest thusly in your
>> transportation:http://www.yellowjersey.org/EASTMAN.HTML
>
> Andrew Muzi must be brave, quick or both:
> <http://www.yellowjersey.org/ EASTMAN6.JPG> - note the Metro bus
> bearing down. My experience with Madison Metro [1] drivers is that
> there is a decent percentage who would just as well run someone over
> as brake or steer out of the way. However, the Eastman Roadster is
> likely solid enough to survive a collision with the mopeds that
> plague downtown Madison (when school is in session) without real
> damage.
>
> [1] <http://www.ci.madison.wi.us/metro/>.
$750 for a Brooks Swallow? Hmmm.
|
| | | |
Date: 24 Jun 2007 18:14:50
From: A Muzi
Subject: Re: Eastman Roadster
|
>> On Jun 23, 8:48 am, "jim beam" (who?) anonymously wrote:
>>> arise komrades of ameristan! free yourselves of your kapitalist
>>> shackles! invest thusly in your
>>> transportation:http://www.yellowjersey.org/EASTMAN.HTML
> Johnny Sunset wrote:
>> Andrew Muzi must be brave, quick or both:
>> <http://www.yellowjersey.org/ EASTMAN6.JPG> - note the Metro bus
>> bearing down. My experience with Madison Metro [1] drivers is that
>> there is a decent percentage who would just as well run someone over
>> as brake or steer out of the way. However, the Eastman Roadster is
>> likely solid enough to survive a collision with the mopeds that
>> plague downtown Madison (when school is in session) without real
>> damage.
>> [1] <http://www.ci.madison.wi.us/metro/>.
Bill Sornson wrote:
> $750 for a Brooks Swallow? Hmmm.
Yep, off price too (SRP $795!). As mentioned in a concurrent thread,
purchases are optional, no coercion.
The new new new model Brooks Swallow has both a hand-stitched edge _and_
a skived (lighter) titanium adjuster unlike the obsolete $399 2006 model.
The essence of marketing is, as always, "This new widget is much
improved over the useless junk we were flogging last season"
Other Brooks, from $72, are not all that different in ride from the
top-of-range 2007 Swallow. Brooks notes that each Swallow is sewn by the
same guy who stitches the Queen's horse saddles. Make of that what you will.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| |
Date: 23 Jun 2007 08:51:05
From:
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 23, 3:16 pm, Ozark Bicycle
<bicycleatel...@ozarkbicycleservice.com > wrote:
> On Jun 23, 8:48 am, jim beam <spamvor...@bad.example.net> wrote:
>
> > invest thusly in your transportation:http://www.yellowjersey.org/EASTMAN.HTML
>
> That bike is at least honest to it's purpose. IMO, much more
> "respectable" in that sense than an over-hyped BS-driven "innovation"
> like a set of Ksyrium SLs or Mavic's "latest breakthrough".
It may be true to it's purpose, but paying $400-$1000 (yep, it's a
grand if you take the SRAM 7-speed and 700c wheels options) is as much
of a conceit as buying Ksyrium ESs "Just like the pros ride" even
though a $200 shimano wheel is better. The modern, not already rusty
before you get it, low maintenance Trek Lime Lite is only $500
|
| | |
Date: 24 Jun 2007 16:48:22
From: A Muzi
Subject: Re: Mavic introduces wheel with compression spokes
|
>> jim beam <spamvor...@bad.example.net> wrote:
>>> invest thusly in your transportation:http://www.yellowjersey.org/EASTMAN.HTML
>Ozark Bicycle <bicycleatel...@ozarkbicycleservice.com> wrote:
>> That bike is at least honest to it's purpose. IMO, much more
>> "respectable" in that sense than an over-hyped BS-driven "innovation"
>> like a set of Ksyrium SLs or Mavic's "latest breakthrough".
google@grafixbyjorj.net wrote:
> It may be true to it's purpose, but paying $400-$1000 (yep, it's a
> grand if you take the SRAM 7-speed and 700c wheels options) is as much
> of a conceit as buying Ksyrium ESs "Just like the pros ride" even
> though a $200 shimano wheel is better. The modern, not already rusty
> before you get it, low maintenance Trek Lime Lite is only $500
And the Raleigh USA "Coasting" version just like the Trek Lime is $429.
(Green w/silver instead of silver w/green) So what?
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| |
Date: 23 Jun 2007 07:16:46
From: Ozark Bicycle
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 23, 8:48 am, jim beam <spamvor...@bad.example.net > wrote:
> Ozark Bicycle wrote:
> > On Jun 23, 8:20 am, jim beam <spamvor...@bad.example.net> wrote:
> >> Ozark Bicycle wrote:
> >>> On Jun 22, 9:08 pm, jim beam <spamvor...@bad.example.net> wrote:
> >>>> Ozark Bicycle wrote:
> >>>>> On Jun 21, 11:31 pm, jim beam <spamvor...@bad.example.net> wrote:
> >>>>>> Ron Ruff wrote:
> >>>>>>> On Jun 19, 9:42 pm, jim beam <spamvor...@bad.example.net> wrote:
> >>>>>>>> now, if we know [and understand] our wheel theory, one could ask oneself
> >>>>>>>> how it's possible to have tension on one side of a wheel and compression
> >>>>>>>> on the other, right? any takers?
> >>>>>>> Yes jim, it is BS... and I'm sure Mavic knows this... but that never
> >>>>>>> stopped them from "reinventing the wheel" before!
> >>>>>> hold on: did mavic write this story? or was it written by a journalist
> >>>>>> - that's not good at math?
> >>>>>>> Obviously, the NDS
> >>>>>>> carbon spokes must be in tension if the DS spokes are, or the wheel
> >>>>>>> couldn't be centered. Also how much compressive load could a 4mm dia
> >>>>>>> 270mm long tube take before it buckled? Very little I'm sure.
> >>>>>> indeed.
> >>>>>>> It isn't hard to make a set of wheels that weighs the same as these
> >>>>>>> (1380g) for half the money. They'd be more aerodynamic, and probably
> >>>>>>> as stiff and durable... and certainly much easier and cheaper to
> >>>>>>> service and repair. But I bet Mavic sells enough of these to make a
> >>>>>>> lot of money... they know how to market stuff to the avg consumer.
> >>>>>> and making money is un-american.
> >>>>> Informed, intelligent cyclists avoid feeding the greed pigs.
> >>>> my! the socialist republic of r.b.t!-
> >>> Perhaps you'd be happier at rec.bicycles.manipulated-sucker
> >> excuse me? who is it here that's pointing out the the b.s. with these
> >> alleged "compression spokes"? i just think that if someone wants to buy
> >> this stuff, they should have that freedom.
>
> > Of course they should. And they do. But, IMO, intelligent, informed
> > cyclists will approach things with a skeptical attitude and make
> > informed purchases. That approach doesn't serve the greed pigs.
>
> arise komrades of ameristan! free yourselves of your kapitalist
> shackles!
So you equate an intelligent, informed approach to making purchases
with communism, eh? That's an interesting insight into your mentality.
> invest thusly in your transportation:http://www.yellowjersey.org/EASTMAN.HTML
>
That bike is at least honest to it's purpose. IMO, much more
"respectable" in that sense than an over-hyped BS-driven "innovation"
like a set of Ksyrium SLs or Mavic's "latest breakthrough".
|
| | |
Date: 24 Jun 2007 16:17:56
From: A Muzi
Subject: Re: Mavic introduces wheel with compression spokes
|
-snip-
> jim beam <spamvor...@bad.example.net> wrote:
>> arise komrades of ameristan! free yourselves of your kapitalist
>> shackles!
>> invest thusly in your transportation:http://www.yellowjersey.org/EASTMAN.HTML
Ozark Bicycle wrote:
> So you equate an intelligent, informed approach to making purchases
> with communism, eh? That's an interesting insight into your mentality.
> That bike is at least honest to it's purpose. IMO, much more
> "respectable" in that sense than an over-hyped BS-driven "innovation"
> like a set of Ksyrium SLs or Mavic's "latest breakthrough".
I've lost the point here but I'd take frou-frou Mavic wheels over steel
28-inch Roadster wheels any day myself (glad those aren't the only choices!)
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | |
Date: 23 Jun 2007 07:42:49
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
Ozark Bicycle wrote:
> On Jun 23, 8:48 am, jim beam <spamvor...@bad.example.net> wrote:
>> Ozark Bicycle wrote:
>>> On Jun 23, 8:20 am, jim beam <spamvor...@bad.example.net> wrote:
>>>> Ozark Bicycle wrote:
>>>>> On Jun 22, 9:08 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>>>> Ozark Bicycle wrote:
>>>>>>> On Jun 21, 11:31 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>>>>>> Ron Ruff wrote:
>>>>>>>>> On Jun 19, 9:42 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>>>>>>>> now, if we know [and understand] our wheel theory, one could ask oneself
>>>>>>>>>> how it's possible to have tension on one side of a wheel and compression
>>>>>>>>>> on the other, right? any takers?
>>>>>>>>> Yes jim, it is BS... and I'm sure Mavic knows this... but that never
>>>>>>>>> stopped them from "reinventing the wheel" before!
>>>>>>>> hold on: did mavic write this story? or was it written by a journalist
>>>>>>>> - that's not good at math?
>>>>>>>>> Obviously, the NDS
>>>>>>>>> carbon spokes must be in tension if the DS spokes are, or the wheel
>>>>>>>>> couldn't be centered. Also how much compressive load could a 4mm dia
>>>>>>>>> 270mm long tube take before it buckled? Very little I'm sure.
>>>>>>>> indeed.
>>>>>>>>> It isn't hard to make a set of wheels that weighs the same as these
>>>>>>>>> (1380g) for half the money. They'd be more aerodynamic, and probably
>>>>>>>>> as stiff and durable... and certainly much easier and cheaper to
>>>>>>>>> service and repair. But I bet Mavic sells enough of these to make a
>>>>>>>>> lot of money... they know how to market stuff to the avg consumer.
>>>>>>>> and making money is un-american.
>>>>>>> Informed, intelligent cyclists avoid feeding the greed pigs.
>>>>>> my! the socialist republic of r.b.t!-
>>>>> Perhaps you'd be happier at rec.bicycles.manipulated-sucker
>>>> excuse me? who is it here that's pointing out the the b.s. with these
>>>> alleged "compression spokes"? i just think that if someone wants to buy
>>>> this stuff, they should have that freedom.
>>> Of course they should. And they do. But, IMO, intelligent, informed
>>> cyclists will approach things with a skeptical attitude and make
>>> informed purchases. That approach doesn't serve the greed pigs.
>> arise komrades of ameristan! free yourselves of your kapitalist
>> shackles!
>
> So you equate an intelligent, informed approach to making purchases
> with communism, eh? That's an interesting insight into your mentality.
no dude, i equate knee-jerk dismissal of anything new as small minded
and rather unintelligent. some stuff may be b.s., but not all of it is.
the bottom line is that the majority of the caterwauling and ire
provoked in these debates, in reality, comes from economics, not technology.
so what if stuff is expensive? don't buy it! but sheeple lining up to
[uninformedly] criticize something as technically deficient when their
real agenda is that they don't like not being able to afford it, is
bullshit. if they can't afford it and want to bemoan prices, go ahead!
but don't fabricate b.s. about a ceramic bearing set being technically
deficient just because of the $240 price tag.
>
>
>> invest thusly in your transportation:http://www.yellowjersey.org/EASTMAN.HTML
>>
>
> That bike is at least honest to it's purpose. IMO, much more
> "respectable" in that sense than an over-hyped BS-driven "innovation"
> like a set of Ksyrium SLs or Mavic's "latest breakthrough".
>
truthfully, i like that bike too - that's why i cited it. and i haven't
cared to buy ksyrium sl's because i've seen too many people stuck at the
side of the road with broken spokes. but the low end ksyriums are just
dandy and the concept of pre-built wheels, in my opinion, is a great
thing given the very poor quality of the average lbs wheelbuild.
i say keep an open mind and play each "tech innovation" ball as it comes.
|
| |
Date: 23 Jun 2007 06:30:08
From: Ozark Bicycle
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 23, 8:20 am, jim beam <spamvor...@bad.example.net > wrote:
> Ozark Bicycle wrote:
> > On Jun 22, 9:08 pm, jim beam <spamvor...@bad.example.net> wrote:
> >> Ozark Bicycle wrote:
> >>> On Jun 21, 11:31 pm, jim beam <spamvor...@bad.example.net> wrote:
> >>>> Ron Ruff wrote:
> >>>>> On Jun 19, 9:42 pm, jim beam <spamvor...@bad.example.net> wrote:
> >>>>>> now, if we know [and understand] our wheel theory, one could ask oneself
> >>>>>> how it's possible to have tension on one side of a wheel and compression
> >>>>>> on the other, right? any takers?
> >>>>> Yes jim, it is BS... and I'm sure Mavic knows this... but that never
> >>>>> stopped them from "reinventing the wheel" before!
> >>>> hold on: did mavic write this story? or was it written by a journalist
> >>>> - that's not good at math?
> >>>>> Obviously, the NDS
> >>>>> carbon spokes must be in tension if the DS spokes are, or the wheel
> >>>>> couldn't be centered. Also how much compressive load could a 4mm dia
> >>>>> 270mm long tube take before it buckled? Very little I'm sure.
> >>>> indeed.
> >>>>> It isn't hard to make a set of wheels that weighs the same as these
> >>>>> (1380g) for half the money. They'd be more aerodynamic, and probably
> >>>>> as stiff and durable... and certainly much easier and cheaper to
> >>>>> service and repair. But I bet Mavic sells enough of these to make a
> >>>>> lot of money... they know how to market stuff to the avg consumer.
> >>>> and making money is un-american.
> >>> Informed, intelligent cyclists avoid feeding the greed pigs.
> >> my! the socialist republic of r.b.t!-
>
> > Perhaps you'd be happier at rec.bicycles.manipulated-sucker
>
> excuse me? who is it here that's pointing out the the b.s. with these
> alleged "compression spokes"? i just think that if someone wants to buy
> this stuff, they should have that freedom.
Of course they should. And they do. But, IMO, intelligent, informed
cyclists will approach things with a skeptical attitude and make
informed purchases. That approach doesn't serve the greed pigs.
> just like people have
> freedom to buy a lamborghini if they want. can't drive it more than 70
> in ca, so the value in terms of speed is wasted, but if people want
> italian bling why not? can't take it with you when you go.- Hide quoted text -
>
> - Show quoted text -
|
| | |
Date: 24 Jun 2007 15:59:39
From: A Muzi
Subject: Re: Mavic introduces wheel with compression spokes
|
Ozark Bicycle wrote:
> Of course they should. And they do. But, IMO, intelligent, informed
> cyclists will approach things with a skeptical attitude and make
> informed purchases. That approach doesn't serve the greed pigs.
There's something wrong with greed?
Hey I don't care for them myself but last I heard nobody's arm was
twisted during a sale...
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | |
Date: 23 Jun 2007 06:48:47
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
Ozark Bicycle wrote:
> On Jun 23, 8:20 am, jim beam <spamvor...@bad.example.net> wrote:
>> Ozark Bicycle wrote:
>>> On Jun 22, 9:08 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>> Ozark Bicycle wrote:
>>>>> On Jun 21, 11:31 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>>>> Ron Ruff wrote:
>>>>>>> On Jun 19, 9:42 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>>>>>> now, if we know [and understand] our wheel theory, one could ask oneself
>>>>>>>> how it's possible to have tension on one side of a wheel and compression
>>>>>>>> on the other, right? any takers?
>>>>>>> Yes jim, it is BS... and I'm sure Mavic knows this... but that never
>>>>>>> stopped them from "reinventing the wheel" before!
>>>>>> hold on: did mavic write this story? or was it written by a journalist
>>>>>> - that's not good at math?
>>>>>>> Obviously, the NDS
>>>>>>> carbon spokes must be in tension if the DS spokes are, or the wheel
>>>>>>> couldn't be centered. Also how much compressive load could a 4mm dia
>>>>>>> 270mm long tube take before it buckled? Very little I'm sure.
>>>>>> indeed.
>>>>>>> It isn't hard to make a set of wheels that weighs the same as these
>>>>>>> (1380g) for half the money. They'd be more aerodynamic, and probably
>>>>>>> as stiff and durable... and certainly much easier and cheaper to
>>>>>>> service and repair. But I bet Mavic sells enough of these to make a
>>>>>>> lot of money... they know how to market stuff to the avg consumer.
>>>>>> and making money is un-american.
>>>>> Informed, intelligent cyclists avoid feeding the greed pigs.
>>>> my! the socialist republic of r.b.t!-
>>> Perhaps you'd be happier at rec.bicycles.manipulated-sucker
>> excuse me? who is it here that's pointing out the the b.s. with these
>> alleged "compression spokes"? i just think that if someone wants to buy
>> this stuff, they should have that freedom.
>
> Of course they should. And they do. But, IMO, intelligent, informed
> cyclists will approach things with a skeptical attitude and make
> informed purchases. That approach doesn't serve the greed pigs.
arise komrades of ameristan! free yourselves of your kapitalist
shackles! invest thusly in your transportation:
http://www.yellowjersey.org/EASTMAN.HTML
>
>
>
>> just like people have
>> freedom to buy a lamborghini if they want. can't drive it more than 70
>> in ca, so the value in terms of speed is wasted, but if people want
>> italian bling why not? can't take it with you when you go.- Hide quoted text -
>>
>> - Show quoted text -
>
>
|
| |
Date: 23 Jun 2007 03:59:56
From: Ozark Bicycle
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 22, 9:08 pm, jim beam <spamvor...@bad.example.net > wrote:
> Ozark Bicycle wrote:
> > On Jun 21, 11:31 pm, jim beam <spamvor...@bad.example.net> wrote:
> >> Ron Ruff wrote:
> >>> On Jun 19, 9:42 pm, jim beam <spamvor...@bad.example.net> wrote:
> >>>> now, if we know [and understand] our wheel theory, one could ask oneself
> >>>> how it's possible to have tension on one side of a wheel and compression
> >>>> on the other, right? any takers?
> >>> Yes jim, it is BS... and I'm sure Mavic knows this... but that never
> >>> stopped them from "reinventing the wheel" before!
> >> hold on: did mavic write this story? or was it written by a journalist
> >> - that's not good at math?
>
> >>> Obviously, the NDS
> >>> carbon spokes must be in tension if the DS spokes are, or the wheel
> >>> couldn't be centered. Also how much compressive load could a 4mm dia
> >>> 270mm long tube take before it buckled? Very little I'm sure.
> >> indeed.
>
> >>> It isn't hard to make a set of wheels that weighs the same as these
> >>> (1380g) for half the money. They'd be more aerodynamic, and probably
> >>> as stiff and durable... and certainly much easier and cheaper to
> >>> service and repair. But I bet Mavic sells enough of these to make a
> >>> lot of money... they know how to market stuff to the avg consumer.
> >> and making money is un-american.
>
> > Informed, intelligent cyclists avoid feeding the greed pigs.
>
> my! the socialist republic of r.b.t!-
Perhaps you'd be happier at rec.bicycles.manipulated-sucker
|
| | |
Date: 23 Jun 2007 06:20:03
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
Ozark Bicycle wrote:
> On Jun 22, 9:08 pm, jim beam <spamvor...@bad.example.net> wrote:
>> Ozark Bicycle wrote:
>>> On Jun 21, 11:31 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>> Ron Ruff wrote:
>>>>> On Jun 19, 9:42 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>>>> now, if we know [and understand] our wheel theory, one could ask oneself
>>>>>> how it's possible to have tension on one side of a wheel and compression
>>>>>> on the other, right? any takers?
>>>>> Yes jim, it is BS... and I'm sure Mavic knows this... but that never
>>>>> stopped them from "reinventing the wheel" before!
>>>> hold on: did mavic write this story? or was it written by a journalist
>>>> - that's not good at math?
>>>>> Obviously, the NDS
>>>>> carbon spokes must be in tension if the DS spokes are, or the wheel
>>>>> couldn't be centered. Also how much compressive load could a 4mm dia
>>>>> 270mm long tube take before it buckled? Very little I'm sure.
>>>> indeed.
>>>>> It isn't hard to make a set of wheels that weighs the same as these
>>>>> (1380g) for half the money. They'd be more aerodynamic, and probably
>>>>> as stiff and durable... and certainly much easier and cheaper to
>>>>> service and repair. But I bet Mavic sells enough of these to make a
>>>>> lot of money... they know how to market stuff to the avg consumer.
>>>> and making money is un-american.
>>> Informed, intelligent cyclists avoid feeding the greed pigs.
>> my! the socialist republic of r.b.t!-
>
> Perhaps you'd be happier at rec.bicycles.manipulated-sucker
>
excuse me? who is it here that's pointing out the the b.s. with these
alleged "compression spokes"? i just think that if someone wants to buy
this stuff, they should have that freedom. just like people have
freedom to buy a lamborghini if they want. can't drive it more than 70
in ca, so the value in terms of speed is wasted, but if people want
italian bling why not? can't take it with you when you go.
|
| |
Date: 22 Jun 2007 22:24:57
From: Ron Ruff
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 22, 10:25 pm, jim beam <spamvor...@bad.example.net > wrote:
> where do you get that from? the geometry doesn't change, therefore the
> ratio doesn't change.
Let's say that the tension ratio is 2 to 1... NDS= 50kg, and DS=
100kg. As you move the rim vertically, the change in tension will be
nearly the same, so when the NDS gets down to 10kg the DS will be
60kg... so now the ratio is 6 to 1. In the real world the rest of the
wheel will be involved, and also the rim will move sideways... and the
same thing will happen with compression spokes.
> again, where does all this stuff come from? download damon rinard's
> spoke calc spreadsheet.http://sheldonbrown.com/rinard/spocalc.xls
> the tension ratio is in there. you'd have to have some pretty loopy hub
> flange spacing to get only 20%.
Loopy maybe, but easy to do. Make the DS spacing 10mm (instead of the
typical 18mm) and the NDS spacing 50mm and there you have it.
|
| | |
Date: 23 Jun 2007 06:19:28
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
Ron Ruff wrote:
> On Jun 22, 10:25 pm, jim beam <spamvor...@bad.example.net> wrote:
>> where do you get that from? the geometry doesn't change, therefore the
>> ratio doesn't change.
>
> Let's say that the tension ratio is 2 to 1... NDS= 50kg, and DS=
> 100kg. As you move the rim vertically, the change in tension will be
> nearly the same, so when the NDS gets down to 10kg the DS will be
> 60kg... so now the ratio is 6 to 1.
doesn't work like that. if the ratio is 2:1 and drive side drops to
50kgf, nds will be 25kgf. if it drops to 0.001kgf ds, nds drops to
0.0005kgf. ratio is fixed by geometry. you'd have to change geometry
to change ratio, not tension.
> In the real world the rest of the
> wheel will be involved, and also the rim will move sideways... and the
> same thing will happen with compression spokes.
said that before: lateral loading is the only way you can observe a
different tension ratio.
>
>> again, where does all this stuff come from? download damon rinard's
>> spoke calc spreadsheet.http://sheldonbrown.com/rinard/spocalc.xls
>> the tension ratio is in there. you'd have to have some pretty loopy hub
>> flange spacing to get only 20%.
>
> Loopy maybe, but easy to do. Make the DS spacing 10mm (instead of the
> typical 18mm) and the NDS spacing 50mm and there you have it.
right, but it's not 10mm:50mm and it's not variable!
|
| |
Date: 22 Jun 2007 20:34:13
From: Ron Ruff
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 22, 7:59 pm, jim beam <spamvor...@bad.example.net > wrote:
> not possible from radial loading without the drive side spokes going
> slack. tension ratio is a matter of geometry. if the ratio is 50%,
> it's 50% and can't change regardless of tension magnitude - if one side
> goes into compression, the other does too. and you can't compress those
> aluminum spokes.
You might be forgetting about the stiffness of the rim spreading loads
out, and the rim can also move laterally. Look at what would happen if
you moved the bottom of the rim vertically on a normal wheel. The
*change* in tension will be nearly the same on both sides... but the
tension *ratio* would change a lot. Obviously, the rim spreads the
load out some and the rim also moves lateral when there is a pure
vertical load.
A journalist thinks he remembers hearing that the rear Mavic wheel has
a 5 to 1 tension ratio... 100kg vs 20kg. Also, if I did the
calculations correctly, the carbon tubes should be able to take ~1200N
(or 120kg) in compression before buckling. So I'm starting to think
that they at least have a wheel that works sort of like they say it
does.
|
| | |
Date: 22 Jun 2007 21:25:25
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
Ron Ruff wrote:
> On Jun 22, 7:59 pm, jim beam <spamvor...@bad.example.net> wrote:
>> not possible from radial loading without the drive side spokes going
>> slack. tension ratio is a matter of geometry. if the ratio is 50%,
>> it's 50% and can't change regardless of tension magnitude - if one side
>> goes into compression, the other does too. and you can't compress those
>> aluminum spokes.
>
> You might be forgetting about the stiffness of the rim spreading loads
> out, and the rim can also move laterally. Look at what would happen if
> you moved the bottom of the rim vertically on a normal wheel. The
> *change* in tension will be nearly the same on both sides... but the
> tension *ratio* would change a lot.
where do you get that from? the geometry doesn't change, therefore the
ratio doesn't change.
> Obviously, the rim spreads the
> load out some and the rim also moves lateral when there is a pure
> vertical load.
>
> A journalist thinks he remembers hearing that the rear Mavic wheel has
> a 5 to 1 tension ratio... 100kg vs 20kg.
again, where does all this stuff come from? download damon rinard's
spoke calc spreadsheet.
http://sheldonbrown.com/rinard/spocalc.xls
the tension ratio is in there. you'd have to have some pretty loopy hub
flange spacing to get only 20%.
> Also, if I did the
> calculations correctly, the carbon tubes should be able to take ~1200N
> (or 120kg) in compression before buckling.
same mathematician as the 20% tension ratio guy?
> So I'm starting to think
> that they at least have a wheel that works sort of like they say it
> does.
people on r.b.t believe all kinds of stuff.
|
| |
Date: 22 Jun 2007 15:36:25
From: Ozark Bicycle
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 21, 11:31 pm, jim beam <spamvor...@bad.example.net > wrote:
> Ron Ruff wrote:
> > On Jun 19, 9:42 pm, jim beam <spamvor...@bad.example.net> wrote:
> >> now, if we know [and understand] our wheel theory, one could ask oneself
> >> how it's possible to have tension on one side of a wheel and compression
> >> on the other, right? any takers?
>
> > Yes jim, it is BS... and I'm sure Mavic knows this... but that never
> > stopped them from "reinventing the wheel" before!
>
> hold on: did mavic write this story? or was it written by a journalist
> - that's not good at math?
>
> > Obviously, the NDS
> > carbon spokes must be in tension if the DS spokes are, or the wheel
> > couldn't be centered. Also how much compressive load could a 4mm dia
> > 270mm long tube take before it buckled? Very little I'm sure.
>
> indeed.
>
>
>
> > It isn't hard to make a set of wheels that weighs the same as these
> > (1380g) for half the money. They'd be more aerodynamic, and probably
> > as stiff and durable... and certainly much easier and cheaper to
> > service and repair. But I bet Mavic sells enough of these to make a
> > lot of money... they know how to market stuff to the avg consumer.
>
> and making money is un-american.
Informed, intelligent cyclists avoid feeding the greed pigs.
|
| | |
Date: 24 Jun 2007 14:27:02
From: A Muzi
Subject: Re: Mavic introduces wheel with compression spokes
|
>>>> now, if we know [and understand] our wheel theory, one could ask oneself
>>>> how it's possible to have tension on one side of a wheel and compression
>>>> on the other, right? any takers?
>>> Yes jim, it is BS... and I'm sure Mavic knows this... but that never
>>> stopped them from "reinventing the wheel" before!
>> hold on: did mavic write this story? or was it written by a journalist
>> - that's not good at math?
>>> jim beam <spamvor...@bad.example.net> wrote:
>>> Obviously, the NDS
>>> carbon spokes must be in tension if the DS spokes are, or the wheel
>>> couldn't be centered. Also how much compressive load could a 4mm dia
>>> 270mm long tube take before it buckled? Very little I'm sure.
>> indeed.
>> Ron Ruff wrote:
>>> It isn't hard to make a set of wheels that weighs the same as these
>>> (1380g) for half the money. They'd be more aerodynamic, and probably
>>> as stiff and durable... and certainly much easier and cheaper to
>>> service and repair. But I bet Mavic sells enough of these to make a
>>> lot of money... they know how to market stuff to the avg consumer.
> jim beam <spamvor...@bad.example.net> wrote:
>> and making money is un-american.
Ozark Bicycle wrote:
> Informed, intelligent cyclists avoid feeding the greed pigs.
OK, but _somebody_ buys them - or they'd stop making 'em!
Tom Hesselman reports this week that a major (Acre of Bikes!) dealer in
Milwaukee had not one set of spokes for sale, any length, in the house.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | | |
Date: 24 Jun 2007 12:34:38
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
A Muzi wrote:
>>>>> now, if we know [and understand] our wheel theory, one could ask
>>>>> oneself
>>>>> how it's possible to have tension on one side of a wheel and
>>>>> compression
>>>>> on the other, right? any takers?
>>>> Yes jim, it is BS... and I'm sure Mavic knows this... but that never
>>>> stopped them from "reinventing the wheel" before!
>>> hold on: did mavic write this story? or was it written by a journalist
>>> - that's not good at math?
>
>>>> jim beam <spamvor...@bad.example.net> wrote:
>>>> Obviously, the NDS
>>>> carbon spokes must be in tension if the DS spokes are, or the wheel
>>>> couldn't be centered. Also how much compressive load could a 4mm dia
>>>> 270mm long tube take before it buckled? Very little I'm sure.
>>> indeed.
>
>>> Ron Ruff wrote:
>>>> It isn't hard to make a set of wheels that weighs the same as these
>>>> (1380g) for half the money. They'd be more aerodynamic, and probably
>>>> as stiff and durable... and certainly much easier and cheaper to
>>>> service and repair. But I bet Mavic sells enough of these to make a
>>>> lot of money... they know how to market stuff to the avg consumer.
>
>> jim beam <spamvor...@bad.example.net> wrote:
>>> and making money is un-american.
>
> Ozark Bicycle wrote:
>> Informed, intelligent cyclists avoid feeding the greed pigs.
>
> OK, but _somebody_ buys them - or they'd stop making 'em!
>
> Tom Hesselman reports this week that a major (Acre of Bikes!) dealer in
> Milwaukee had not one set of spokes for sale, any length, in the house.
sad, but from the average end user perspective, selling spokes is about
as much use as selling frame tube.
|
| | |
Date: 22 Jun 2007 19:08:58
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
Ozark Bicycle wrote:
> On Jun 21, 11:31 pm, jim beam <spamvor...@bad.example.net> wrote:
>> Ron Ruff wrote:
>>> On Jun 19, 9:42 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>> now, if we know [and understand] our wheel theory, one could ask oneself
>>>> how it's possible to have tension on one side of a wheel and compression
>>>> on the other, right? any takers?
>>> Yes jim, it is BS... and I'm sure Mavic knows this... but that never
>>> stopped them from "reinventing the wheel" before!
>> hold on: did mavic write this story? or was it written by a journalist
>> - that's not good at math?
>>
>>> Obviously, the NDS
>>> carbon spokes must be in tension if the DS spokes are, or the wheel
>>> couldn't be centered. Also how much compressive load could a 4mm dia
>>> 270mm long tube take before it buckled? Very little I'm sure.
>> indeed.
>>
>>
>>
>>> It isn't hard to make a set of wheels that weighs the same as these
>>> (1380g) for half the money. They'd be more aerodynamic, and probably
>>> as stiff and durable... and certainly much easier and cheaper to
>>> service and repair. But I bet Mavic sells enough of these to make a
>>> lot of money... they know how to market stuff to the avg consumer.
>> and making money is un-american.
>
> Informed, intelligent cyclists avoid feeding the greed pigs.
>
my! the socialist republic of r.b.t!
|
| |
Date: 22 Jun 2007 17:22:53
From: Gary Young
Subject: Re: Mavic introduces wheel with compression spokes
|
On Fri, 22 Jun 2007 17:28:48 +0100, Kinky Cowboy wrote:
> On Thu, 21 Jun 2007 21:34:22 -0700, jim beam
> <spamvortex@bad.example.net> wrote:
>
>>steve wrote:
>>> On Jun 21, 12:04 am, jim beam <spamvor...@bad.example.net> wrote:
>>>> steve wrote:
>>>>> On Jun 20, 8:51 am, jim beam <spamvor...@bad.example.net> wrote:
>>>>>> Gary Young wrote:
>>>>>>> Another blog posting on the wheel:
>>>>>>> http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html
>>>>>>> The description seems to me to be hopelessly confused, but there is a
>>>>>>> photograph showing how the carbon-fiber spokes connect to the hub.
>>>>>> well /this/http://rodale.typepad.com/.shared/image.html?/photos/uncategorized/20...
>>>>>> sure isn't a compression fitting!
>>>>> According towww.cyclingnews.comthe carbon spokes are in tension but
>>>>> are designed to handle compressive loads as well.
>>>> that's what the journalists write, but it's clearly not possible from
>>>> that picture.
>>>>
>>>> Mavic has an end cap that presses into the end of the hub to prevent the spokes from being able to move vertically and allow them to take compressive loads. This site describes it a bit more elequently http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html.
>>>
>>> Steve Sauter
>>>
>>ok, thanks for that. but you're still not going to get compression on
>>one side of the rear and tension on the other.
>
> Not on an unloaded wheel. Add some side load from the road and all
> bets are off.
> Kinky Cowboy*
>
> *Batteries not included
> May contain traces of nuts
> Your milage may vary
If the left side spokes are lightly tensioned, then they may go into
compression as they pass the contact patch. Only a few spokes would be in
compression. Wouldn't the remaining spokes in tension be enough to ensure
the structural integrity of the wheel? (At least when the wheel doesn't
encounter large lateral loads, since the low tension means a weak wheel.)
Mind you, I'm not trying to say that this is a good idea.
|
| | |
Date: 22 Jun 2007 18:59:59
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
Gary Young wrote:
> On Fri, 22 Jun 2007 17:28:48 +0100, Kinky Cowboy wrote:
>
>> On Thu, 21 Jun 2007 21:34:22 -0700, jim beam
>> <spamvortex@bad.example.net> wrote:
>>
>>> steve wrote:
>>>> On Jun 21, 12:04 am, jim beam <spamvor...@bad.example.net> wrote:
>>>>> steve wrote:
>>>>>> On Jun 20, 8:51 am, jim beam <spamvor...@bad.example.net> wrote:
>>>>>>> Gary Young wrote:
>>>>>>>> Another blog posting on the wheel:
>>>>>>>> http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html
>>>>>>>> The description seems to me to be hopelessly confused, but there is a
>>>>>>>> photograph showing how the carbon-fiber spokes connect to the hub.
>>>>>>> well /this/http://rodale.typepad.com/.shared/image.html?/photos/uncategorized/20...
>>>>>>> sure isn't a compression fitting!
>>>>>> According towww.cyclingnews.comthe carbon spokes are in tension but
>>>>>> are designed to handle compressive loads as well.
>>>>> that's what the journalists write, but it's clearly not possible from
>>>>> that picture.
>>>>>
>>>>> Mavic has an end cap that presses into the end of the hub to prevent the spokes from being able to move vertically and allow them to take compressive loads. This site describes it a bit more elequently http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html.
>>>> Steve Sauter
>>>>
>>> ok, thanks for that. but you're still not going to get compression on
>>> one side of the rear and tension on the other.
>> Not on an unloaded wheel. Add some side load from the road and all
>> bets are off.
>> Kinky Cowboy*
>>
>> *Batteries not included
>> May contain traces of nuts
>> Your milage may vary
>
first off, kinky raises the only situation in which this could be
possible. 10 points!
> If the left side spokes are lightly tensioned, then they may go into
> compression as they pass the contact patch. Only a few spokes would be in
> compression. Wouldn't the remaining spokes in tension be enough to ensure
> the structural integrity of the wheel? (At least when the wheel doesn't
> encounter large lateral loads, since the low tension means a weak wheel.)
> Mind you, I'm not trying to say that this is a good idea.
not possible from radial loading without the drive side spokes going
slack. tension ratio is a matter of geometry. if the ratio is 50%,
it's 50% and can't change regardless of tension magnitude - if one side
goes into compression, the other does too. and you can't compress those
aluminum spokes.
|
| |
Date: 21 Jun 2007 09:36:51
From: Ron Ruff
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 19, 9:42 pm, jim beam <spamvor...@bad.example.net > wrote:
> now, if we know [and understand] our wheel theory, one could ask oneself
> how it's possible to have tension on one side of a wheel and compression
> on the other, right? any takers?
Yes jim, it is BS... and I'm sure Mavic knows this... but that never
stopped them from "reinventing the wheel" before! Obviously, the NDS
carbon spokes must be in tension if the DS spokes are, or the wheel
couldn't be centered. Also how much compressive load could a 4mm dia
270mm long tube take before it buckled? Very little I'm sure.
It isn't hard to make a set of wheels that weighs the same as these
(1380g) for half the money. They'd be more aerodynamic, and probably
as stiff and durable... and certainly much easier and cheaper to
service and repair. But I bet Mavic sells enough of these to make a
lot of money... they know how to market stuff to the avg consumer.
|
| | |
Date: 21 Jun 2007 21:31:59
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
Ron Ruff wrote:
> On Jun 19, 9:42 pm, jim beam <spamvor...@bad.example.net> wrote:
>> now, if we know [and understand] our wheel theory, one could ask oneself
>> how it's possible to have tension on one side of a wheel and compression
>> on the other, right? any takers?
>
> Yes jim, it is BS... and I'm sure Mavic knows this... but that never
> stopped them from "reinventing the wheel" before!
hold on: did mavic write this story? or was it written by a journalist
- that's not good at math?
> Obviously, the NDS
> carbon spokes must be in tension if the DS spokes are, or the wheel
> couldn't be centered. Also how much compressive load could a 4mm dia
> 270mm long tube take before it buckled? Very little I'm sure.
indeed.
>
> It isn't hard to make a set of wheels that weighs the same as these
> (1380g) for half the money. They'd be more aerodynamic, and probably
> as stiff and durable... and certainly much easier and cheaper to
> service and repair. But I bet Mavic sells enough of these to make a
> lot of money... they know how to market stuff to the avg consumer.
and making money is un-american.
|
| |
Date: 21 Jun 2007 06:28:01
From: steve
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 21, 12:04 am, jim beam <spamvor...@bad.example.net > wrote:
> steve wrote:
> > On Jun 20, 8:51 am, jim beam <spamvor...@bad.example.net> wrote:
> >> Gary Young wrote:
> >>> Another blog posting on the wheel:
> >>>http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html
> >>> The description seems to me to be hopelessly confused, but there is a
> >>> photograph showing how the carbon-fiber spokes connect to the hub.
> >> well /this/http://rodale.typepad.com/.shared/image.html?/photos/uncategorized/20...
> >> sure isn't a compression fitting!
>
> > According towww.cyclingnews.comthe carbon spokes are in tension but
> > are designed to handle compressive loads as well.
>
> that's what the journalists write, but it's clearly not possible from
> that picture.
>
> Mavic has an end cap that presses into the end of the hub to prevent the spokes from being able to move vertically and allow them to take compressive loads. This site describes it a bit more elequently http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html.
Steve Sauter
|
| | |
Date: 21 Jun 2007 21:34:22
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
steve wrote:
> On Jun 21, 12:04 am, jim beam <spamvor...@bad.example.net> wrote:
>> steve wrote:
>>> On Jun 20, 8:51 am, jim beam <spamvor...@bad.example.net> wrote:
>>>> Gary Young wrote:
>>>>> Another blog posting on the wheel:
>>>>> http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html
>>>>> The description seems to me to be hopelessly confused, but there is a
>>>>> photograph showing how the carbon-fiber spokes connect to the hub.
>>>> well /this/http://rodale.typepad.com/.shared/image.html?/photos/uncategorized/20...
>>>> sure isn't a compression fitting!
>>> According towww.cyclingnews.comthe carbon spokes are in tension but
>>> are designed to handle compressive loads as well.
>> that's what the journalists write, but it's clearly not possible from
>> that picture.
>>
>> Mavic has an end cap that presses into the end of the hub to prevent the spokes from being able to move vertically and allow them to take compressive loads. This site describes it a bit more elequently http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html.
>
> Steve Sauter
>
ok, thanks for that. but you're still not going to get compression on
one side of the rear and tension on the other.
|
| | | |
Date: 27 Jun 2007 23:43:04
From: Ron Ruff
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 27, 7:40 pm, jobst.bra...@stanfordalumni.org wrote:
> The two go together. The force diagram is one and the same with the
> physical triangle formed by spokes and hub, the forces being coaxial
> with the spokes.
In that case explain the force diagram when a spoke is removed... now
the local tension ratio is say 100kg to zero.
And if you apply a vertical load to a dished wheel, the amount of
tension lost by both sides at the load point will be essentially the
same (cos of small angles) even though the NDS tension was initially
half as much. The lateral forces will no longer be locally balanced
where this load is applied, and the rim will deflect sideways a small
amount, and the tension of the spokes in the rest of the wheel will
compensate as well. There is an entire wheel with a bunch of spokes
involved.
|
| | | | |
Date: 28 Jun 2007 17:29:42
From: Kinky Cowboy
Subject: Re: Mavic introduces wheel with compression spokes
|
On Wed, 27 Jun 2007 23:43:04 -0700, Ron Ruff <rruffrruff@yahoo.com >
wrote:
>On Jun 27, 7:40 pm, jobst.bra...@stanfordalumni.org wrote:
>> The two go together. The force diagram is one and the same with the
>> physical triangle formed by spokes and hub, the forces being coaxial
>> with the spokes.
>
>In that case explain the force diagram when a spoke is removed... now
>the local tension ratio is say 100kg to zero.
>
And the axial component of the spoke tension is balanced by the stress
in the rim as it bends out of plane. Except in the case of co-planar
paired spokes, this is the case whether you remove a spoke or not; the
rim has the bend from one spoke to another to transfer the axial
components of spoke tension across the wheel.
Kinky Cowboy*
*Batteries not included
May contain traces of nuts
Your milage may vary
|
| | | |
Date: 22 Jun 2007 17:28:48
From: Kinky Cowboy
Subject: Re: Mavic introduces wheel with compression spokes
|
On Thu, 21 Jun 2007 21:34:22 -0700, jim beam
<spamvortex@bad.example.net > wrote:
>steve wrote:
>> On Jun 21, 12:04 am, jim beam <spamvor...@bad.example.net> wrote:
>>> steve wrote:
>>>> On Jun 20, 8:51 am, jim beam <spamvor...@bad.example.net> wrote:
>>>>> Gary Young wrote:
>>>>>> Another blog posting on the wheel:
>>>>>> http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html
>>>>>> The description seems to me to be hopelessly confused, but there is a
>>>>>> photograph showing how the carbon-fiber spokes connect to the hub.
>>>>> well /this/http://rodale.typepad.com/.shared/image.html?/photos/uncategorized/20...
>>>>> sure isn't a compression fitting!
>>>> According towww.cyclingnews.comthe carbon spokes are in tension but
>>>> are designed to handle compressive loads as well.
>>> that's what the journalists write, but it's clearly not possible from
>>> that picture.
>>>
>>> Mavic has an end cap that presses into the end of the hub to prevent the spokes from being able to move vertically and allow them to take compressive loads. This site describes it a bit more elequently http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html.
>>
>> Steve Sauter
>>
>ok, thanks for that. but you're still not going to get compression on
>one side of the rear and tension on the other.
Not on an unloaded wheel. Add some side load from the road and all
bets are off.
Kinky Cowboy*
*Batteries not included
May contain traces of nuts
Your milage may vary
|
| |
Date: 21 Jun 2007 04:59:47
From: Qui si parla Campagnolo
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 20, 8:26 am, steve <ssau...@emich.edu > wrote:
> On Jun 20, 8:51 am, jim beam <spamvor...@bad.example.net> wrote:
>
> > Gary Young wrote:
> > > Another blog posting on the wheel:
>
> > >http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html
>
> > > The description seems to me to be hopelessly confused, but there is a
> > > photograph showing how the carbon-fiber spokes connect to the hub.
>
> > well /this/http://rodale.typepad.com/.shared/image.html?/photos/uncategorized/20...
> > sure isn't a compression fitting!
>
> According towww.cyclingnews.comthe carbon spokes are in tension but
> are designed to handle compressive loads as well. This allows them to
> make a wheel with lower spoke tension thus a lighter rim since it
> doesn't have to handle as much stress from the spokes. Mavic has also
> finally given in to the asymetric rim design for there new wheels in
> order to help balance spoke tension. The reason for the aluminum
> spokes on the drive side in the rear wheel is so that they could use
> thin bladed spokes and thus place them as far away from the center of
> the hub as possible. It lookes like the front wheel uses 18 spokes
> and the rear uses 24.
> It sounds like a decent racing wheel to me but I am a bit sceptical
> about how it will hold up for the general public. I did find this
> claim by mavic to be interesting, "In seeking that elusive "third
> generation", Mavic designers and engineers identified spoke stiffness
> and flange spacing as the biggest contributors to a wheel's lateral
> rigidity, while rim stiffness, spoke length, hub flange diameter, and
> spoke lacing patterns all are said to offer little significant
> influence. More surprisingly, Mavic also claims that spoke tension has
> a negligible influence, and increasing the spoke tension actually
> reduces overall lateral rigidity (although it does delay the onset of
> complete spoke detensioning)." I was surprised to hear that rim
> stiffness has such a small influence on lateral stiffness.
It's true when said in French.
I notice a
> huge difference between a deepV rim and a open pro rim when it comes
> to lateral stiffness, assuming the same hub and spokes are used in
> both wheels.
>
> Steve Sauter
|
| | |
Date: 21 Jun 2007 15:02:09
From: Sandy
Subject: Re: Mavic introduces wheel with compression spokes
|
Dans le message de
news:1182427187.541565.116980@d30g2000prg.googlegroups.com,
Qui si parla Campagnolo <peter@vecchios.com > a réfléchi, et puis a déclaré :
> On Jun 20, 8:26 am, steve <ssau...@emich.edu> wrote:
>> On Jun 20, 8:51 am, jim beam <spamvor...@bad.example.net> wrote:
>>
>>> Gary Young wrote:
>>>> Another blog posting on the wheel:
>>
>>>> http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html
>>
>>>> The description seems to me to be hopelessly confused, but there
>>>> is a photograph showing how the carbon-fiber spokes connect to the
>>>> hub.
>>
>>> well
>>> /this/http://rodale.typepad.com/.shared/image.html?/photos/uncategorized/20...
>>> sure isn't a compression fitting!
>>
>> According towww.cyclingnews.comthe carbon spokes are in tension but
>> are designed to handle compressive loads as well. This allows them
>> to make a wheel with lower spoke tension thus a lighter rim since it
>> doesn't have to handle as much stress from the spokes. Mavic has
>> also finally given in to the asymetric rim design for there new
>> wheels in order to help balance spoke tension. The reason for the
>> aluminum spokes on the drive side in the rear wheel is so that they
>> could use thin bladed spokes and thus place them as far away from
>> the center of the hub as possible. It lookes like the front wheel
>> uses 18 spokes and the rear uses 24.
>> It sounds like a decent racing wheel to me but I am a bit sceptical
>> about how it will hold up for the general public. I did find this
>> claim by mavic to be interesting, "In seeking that elusive "third
>> generation", Mavic designers and engineers identified spoke stiffness
>> and flange spacing as the biggest contributors to a wheel's lateral
>> rigidity, while rim stiffness, spoke length, hub flange diameter, and
>> spoke lacing patterns all are said to offer little significant
>> influence. More surprisingly, Mavic also claims that spoke tension
>> has a negligible influence, and increasing the spoke tension actually
>> reduces overall lateral rigidity (although it does delay the onset of
>> complete spoke detensioning)." I was surprised to hear that rim
>> stiffness has such a small influence on lateral stiffness.
>
> It's true when said in French.
Mercy, Peter! You DO love us!! :-)
--
Sandy
--
S'endormir au volant, c'est très dangereux.
S'endormir à vélo, c'est très rare.
S'endormir à pied, c'est très con.
- Geluck, P.
|
| |
Date: 20 Jun 2007 18:44:10
From: steve
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 20, 11:07 am, jobst.bra...@stanfordalumni.org wrote:
> Steve Sauter writes:
>
> http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html
>
> >>> The description seems to me to be hopelessly confused, but there
> >>> is a photograph showing how the carbon-fiber spokes connect to the
> >>> hub.
> >> well /this/
>
> http://tinyurl.com/2m59r9
>
> >> sure isn't a compression fitting!
> > According towww.cyclingnews.comthe carbon spokes are in tension
> > but are designed to handle compressive loads as well. This allows
> > them to make a wheel with lower spoke tension thus a lighter rim
> > since it doesn't have to handle as much stress from the spokes.
> > Mavic has also finally given in to the asymmetric rim design for
> > there new wheels in order to help balance spoke tension. The reason
> > for the aluminum spokes on the drive side in the rear wheel is so
> > that they could use thin bladed spokes and thus place them as far
> > away from the center of the hub as possible. It looks like the
> > front wheel uses 18 spokes and the rear uses 24.
> > It sounds like a decent racing wheel to me but I am a bit skeptical
> > about how it will hold up for the general public.
>
> I don't understand what the difference between racing and other
> bicycling has for wheels. What is it a wheel must do in a race that
> is different from non-race riding. I seem to see differences implied
> that one is a greater stress than the other but the more stressful one
> changes depending on what point is being put forth.
>
> From what I see cruising up and down the avenue here, the all look
> like racing wheels, some costing as much as $4000 a pair, according to
> our local bicycle shops.
>
> Jobst Brandt
I guess I have always viewed a racing wheel as one that must have
great performance, i.e light weight, aerodynamic, or stiff, but not
necessarily durable or able to take varying amounts of stress for long
periods of time. Especially in the upper levels of racing were most
racers are sponsored and performance is all that matters. On the
other hand a wheel that is good for the general public would be one
that has a lot of the characteristics that a race wheel has but is
also durable and able to last a long time without needing to be
maintained. I consider the general public to be people that love to
ride and even compete but do not have disposable incomes or are
sponsored.
Steve Sauter
|
| | |
Date: 21 Jun 2007 03:19:26
From:
Subject: Re: Mavic introduces wheel with compression spokes
|
Steve Sauter writes:
http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html
>>>>> The description seems to me to be hopelessly confused, but there
>>>>> is a photograph showing how the carbon-fiber spokes connect to the
>>>>> hub.
>>>> well /this/
http://tinyurl.com/2m59r9
>>>> sure isn't a compression fitting!
>>> According towww.cyclingnews.comthe carbon spokes are in tension
>>> but are designed to handle compressive loads as well. This allows
>>> them to make a wheel with lower spoke tension thus a lighter rim
>>> since it doesn't have to handle as much stress from the spokes.
>>> Mavic has also finally given in to the asymmetric rim design for
>>> there new wheels in order to help balance spoke tension. The reason
>>> for the aluminum spokes on the drive side in the rear wheel is so
>>> that they could use thin bladed spokes and thus place them as far
>>> away from the center of the hub as possible. It looks like the
>>> front wheel uses 18 spokes and the rear uses 24.
>>> It sounds like a decent racing wheel to me but I am a bit skeptical
>>> about how it will hold up for the general public.
>> I don't understand what the difference between racing and other
>> bicycling has for wheels. What is it a wheel must do in a race that
>> is different from non-race riding. I seem to see differences implied
>> that one is a greater stress than the other but the more stressful one
>> changes depending on what point is being put forth.
>> From what I see cruising up and down the avenue here, the all look
>> like racing wheels, some costing as much as $4000 a pair, according to
>> our local bicycle shops.
> I guess I have always viewed a racing wheel as one that must have
> great performance, i.e. light weight, aerodynamic, or stiff, but not
> necessarily durable or able to take varying amounts of stress for long
> periods of time. Especially in the upper levels of racing were most
> racers are sponsored and performance is all that matters. On the
> other hand a wheel that is good for the general public would be one
> that has a lot of the characteristics that a race wheel has but is
> also durable and able to last a long time without needing to be
> maintained. I consider the general public to be people that love to
> ride and even compete but do not have disposable incomes or are
> sponsored.
I don't believe anyone can design close enough to the failure stress
to make a reliable wheel that will last only an average 500km. Either
the wheel can withstand a mountain stage of a major race or not, and
that can include heavy braking and rough pavement, no different from
what a athletic tourist would encounter. The fragile description
doesn't hold up for what I see as racing... or touring.
Jobst Brandt
|
| | | |
Date: 20 Jun 2007 20:52:19
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
jobst.brandt@stanfordalumni.org wrote:
> Steve Sauter writes:
>
> http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html
>
>>>>>> The description seems to me to be hopelessly confused, but there
>>>>>> is a photograph showing how the carbon-fiber spokes connect to the
>>>>>> hub.
>
>>>>> well /this/
>
> http://tinyurl.com/2m59r9
>
>>>>> sure isn't a compression fitting!
>
>>>> According towww.cyclingnews.comthe carbon spokes are in tension
>>>> but are designed to handle compressive loads as well. This allows
>>>> them to make a wheel with lower spoke tension thus a lighter rim
>>>> since it doesn't have to handle as much stress from the spokes.
>>>> Mavic has also finally given in to the asymmetric rim design for
>>>> there new wheels in order to help balance spoke tension. The reason
>>>> for the aluminum spokes on the drive side in the rear wheel is so
>>>> that they could use thin bladed spokes and thus place them as far
>>>> away from the center of the hub as possible. It looks like the
>>>> front wheel uses 18 spokes and the rear uses 24.
>>>> It sounds like a decent racing wheel to me but I am a bit skeptical
>>>> about how it will hold up for the general public.
>
>>> I don't understand what the difference between racing and other
>>> bicycling has for wheels. What is it a wheel must do in a race that
>>> is different from non-race riding. I seem to see differences implied
>>> that one is a greater stress than the other but the more stressful one
>>> changes depending on what point is being put forth.
>
>>> From what I see cruising up and down the avenue here, the all look
>>> like racing wheels, some costing as much as $4000 a pair, according to
>>> our local bicycle shops.
>
>> I guess I have always viewed a racing wheel as one that must have
>> great performance, i.e. light weight, aerodynamic, or stiff, but not
>> necessarily durable or able to take varying amounts of stress for long
>> periods of time. Especially in the upper levels of racing were most
>> racers are sponsored and performance is all that matters. On the
>> other hand a wheel that is good for the general public would be one
>> that has a lot of the characteristics that a race wheel has but is
>> also durable and able to last a long time without needing to be
>> maintained. I consider the general public to be people that love to
>> ride and even compete but do not have disposable incomes or are
>> sponsored.
>
> I don't believe anyone can design close enough to the failure stress
> to make a reliable wheel that will last only an average 500km.
easy - spoke tension "as high as the rim can bear".
> Either
> the wheel can withstand a mountain stage of a major race or not, and
> that can include heavy braking and rough pavement, no different from
> what a athletic tourist would encounter. The fragile description
> doesn't hold up for what I see as racing... or touring.
>
> Jobst Brandt
|
| |
Date: 20 Jun 2007 18:29:16
From: steve
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 20, 11:00 am, Ron Ruff <rruffrr...@yahoo.com > wrote:
> steve wrote:
> > Mavic designers and engineers identified spoke stiffness
> > and flange spacing as the biggest contributors to a wheel's lateral
> > rigidity, while rim stiffness, spoke length, hub flange diameter, and
> > spoke lacing patterns all are said to offer little significant
> > influence.
>
> When I modeled a wheel I got the same result. Flange spacing (or
> actually bracing angle) has an exponential effect on lateral stiffness
> and the spoke stiffness has almost a linear effect. The rim stiffness
> effect was way below linear.
>
> > I was surprised to hear that rim
> > stiffness has such a small influence on lateral stiffness. I notice a
> > huge difference between a deepV rim and a open pro rim when it comes
> > to lateral stiffness, assuming the same hub and spokes are used in
> > both wheels.
>
> Did you measure this? "Seat of the pants" measurements are unreliable
> for these things... Mavic also built 2 sets of wheels that were
> indentical except that one had 4 times the lateral stiffness of the
> other. Riders could not accurately identify which was which.
Very interesting. I am basing my assumtion off of putting the hub on
the ground and appling a lateral load to both sides of the wheel.
Well you learn something new every day. I guess I don't have the
mathematical knowledge to be able to model a rim of different
stiffnesses to see how it would effect overall wheel stiffness.
On a different note you have to imagine that these new wheels will
have pretty poor aerodynamics with 4mm diameter round spokes.
Steve Sauter
|
| |
Date: 20 Jun 2007 16:39:14
From: Johnny Sunset
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 20, 10:07 am, Jobst Brandt wrote:
> ...What is it a wheel must do in a race that
> is different from non-race riding....
The racing wheel must look cool in the Velonews pictures. No cost
effective, reliable, boring 36-spoke wheels need apply.
--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful
|
| |
Date: 20 Jun 2007 16:09:50
From: Antti Salonen
Subject: Re: Mavic introduces wheel with compression spokes
|
Gary Young <garyyoung3@gmail.com > wrote:
> It was more rigid and at 1355 grams they are one of the
> lighter wheel sets on the market (hey - the spokes only way five grams
> each - versus an aluminum at eight grams - and we know that every gram
> counts)."
The really funny thing is that high-end flat steel spokes like Sapim
CX-Ray or DT Swiss Aerolite are also about five grams each, and they are
a lot more aerodynamic and less likely to break than at least Mavic's
aluminium spokes.
I really can't understand why Mavic insists on using aluminium in
spokes, or carbon for that matter, and why anybody would be stupid
enough to buy them at that price. In the wheel tests perfomed in a wind
tunnel Mavic Ksyrium SL or Ksyrium ES have shown to be about as slow as
wheels get. Mavic Ksyrium Elite or Mavic Aksium ($150 a pair or so) are
faster unless you only ride uphill.
Antti
|
| | |
Date: 20 Jun 2007 20:54:32
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
Antti Salonen wrote:
> Gary Young <garyyoung3@gmail.com> wrote:
>
>> It was more rigid and at 1355 grams they are one of the
>> lighter wheel sets on the market (hey - the spokes only way five grams
>> each - versus an aluminum at eight grams - and we know that every gram
>> counts)."
>
> The really funny thing is that high-end flat steel spokes like Sapim
> CX-Ray or DT Swiss Aerolite are also about five grams each, and they are
> a lot more aerodynamic and less likely to break than at least Mavic's
> aluminium spokes.
indeed! but it's not just weight, it's elasticity.
>
> I really can't understand why Mavic insists on using aluminium in
> spokes, or carbon for that matter, and why anybody would be stupid
> enough to buy them at that price. In the wheel tests perfomed in a wind
> tunnel Mavic Ksyrium SL or Ksyrium ES have shown to be about as slow as
> wheels get. Mavic Ksyrium Elite or Mavic Aksium ($150 a pair or so) are
> faster unless you only ride uphill.
>
> Antti
and that's the reason i've not bought any fat-spoke wheels. the skinny
spoke ones are great though.
|
| |
Date: 20 Jun 2007 08:37:19
From: Ozark Bicycle
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 20, 10:07 am, jobst.bra...@stanfordalumni.org wrote:
> Steve Sauter writes:
>
> http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html
>
> >>> The description seems to me to be hopelessly confused, but there
> >>> is a photograph showing how the carbon-fiber spokes connect to the
> >>> hub.
> >> well /this/
>
> http://tinyurl.com/2m59r9
>
> >> sure isn't a compression fitting!
> > According towww.cyclingnews.comthe carbon spokes are in tension
> > but are designed to handle compressive loads as well. This allows
> > them to make a wheel with lower spoke tension thus a lighter rim
> > since it doesn't have to handle as much stress from the spokes.
> > Mavic has also finally given in to the asymmetric rim design for
> > there new wheels in order to help balance spoke tension. The reason
> > for the aluminum spokes on the drive side in the rear wheel is so
> > that they could use thin bladed spokes and thus place them as far
> > away from the center of the hub as possible. It looks like the
> > front wheel uses 18 spokes and the rear uses 24.
> > It sounds like a decent racing wheel to me but I am a bit skeptical
> > about how it will hold up for the general public.
>
> I don't understand what the difference between racing and other
> bicycling has for wheels. What is it a wheel must do in a race that
> is different from non-race riding.
Lessee....lighter, more aero. IOW, marginally "faster". Less reliable
and durable in pursuit of those goals is okay, too, especially if you
are sponsored and followed around by support vehicles.
> I seem to see differences implied
> that one is a greater stress than the other but the more stressful one
> changes depending on what point is being put forth.
>
> From what I see cruising up and down the avenue here, the all look
> like racing wheels, some costing as much as $4000 a pair, according to
> our local bicycle shops.
>
> Jobst Brandt
|
| |
Date: 20 Jun 2007 15:11:07
From: datakoll
Subject: Re: Mavic introduces wheel with compression spokes
|
what avenue are you cruising?
|
| |
Date: 20 Jun 2007 08:00:26
From: Ron Ruff
Subject: Re: Mavic introduces wheel with compression spokes
|
steve wrote:
> Mavic designers and engineers identified spoke stiffness
> and flange spacing as the biggest contributors to a wheel's lateral
> rigidity, while rim stiffness, spoke length, hub flange diameter, and
> spoke lacing patterns all are said to offer little significant
> influence.
When I modeled a wheel I got the same result. Flange spacing (or
actually bracing angle) has an exponential effect on lateral stiffness
and the spoke stiffness has almost a linear effect. The rim stiffness
effect was way below linear.
> I was surprised to hear that rim
> stiffness has such a small influence on lateral stiffness. I notice a
> huge difference between a deepV rim and a open pro rim when it comes
> to lateral stiffness, assuming the same hub and spokes are used in
> both wheels.
Did you measure this? "Seat of the pants" measurements are unreliable
for these things... Mavic also built 2 sets of wheels that were
indentical except that one had 4 times the lateral stiffness of the
other. Riders could not accurately identify which was which.
|
| |
Date: 20 Jun 2007 07:26:55
From: steve
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 20, 8:51 am, jim beam <spamvor...@bad.example.net > wrote:
> Gary Young wrote:
> > Another blog posting on the wheel:
>
> >http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html
>
> > The description seems to me to be hopelessly confused, but there is a
> > photograph showing how the carbon-fiber spokes connect to the hub.
>
> well /this/http://rodale.typepad.com/.shared/image.html?/photos/uncategorized/20...
> sure isn't a compression fitting!
According to www.cyclingnews.com the carbon spokes are in tension but
are designed to handle compressive loads as well. This allows them to
make a wheel with lower spoke tension thus a lighter rim since it
doesn't have to handle as much stress from the spokes. Mavic has also
finally given in to the asymetric rim design for there new wheels in
order to help balance spoke tension. The reason for the aluminum
spokes on the drive side in the rear wheel is so that they could use
thin bladed spokes and thus place them as far away from the center of
the hub as possible. It lookes like the front wheel uses 18 spokes
and the rear uses 24.
It sounds like a decent racing wheel to me but I am a bit sceptical
about how it will hold up for the general public. I did find this
claim by mavic to be interesting, "In seeking that elusive "third
generation", Mavic designers and engineers identified spoke stiffness
and flange spacing as the biggest contributors to a wheel's lateral
rigidity, while rim stiffness, spoke length, hub flange diameter, and
spoke lacing patterns all are said to offer little significant
influence. More surprisingly, Mavic also claims that spoke tension has
a negligible influence, and increasing the spoke tension actually
reduces overall lateral rigidity (although it does delay the onset of
complete spoke detensioning)." I was surprised to hear that rim
stiffness has such a small influence on lateral stiffness. I notice a
huge difference between a deepV rim and a open pro rim when it comes
to lateral stiffness, assuming the same hub and spokes are used in
both wheels.
Steve Sauter
|
| | |
Date: 20 Jun 2007 21:04:52
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
steve wrote:
> On Jun 20, 8:51 am, jim beam <spamvor...@bad.example.net> wrote:
>> Gary Young wrote:
>>> Another blog posting on the wheel:
>>> http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html
>>> The description seems to me to be hopelessly confused, but there is a
>>> photograph showing how the carbon-fiber spokes connect to the hub.
>> well /this/http://rodale.typepad.com/.shared/image.html?/photos/uncategorized/20...
>> sure isn't a compression fitting!
>
> According to www.cyclingnews.com the carbon spokes are in tension but
> are designed to handle compressive loads as well.
that's what the journalists write, but it's clearly not possible from
that picture.
> This allows them to
> make a wheel with lower spoke tension thus a lighter rim since it
> doesn't have to handle as much stress from the spokes. Mavic has also
> finally given in to the asymetric rim design for there new wheels in
> order to help balance spoke tension.
asymmetry in what? it's only the rim that really matters for asymmetry,
[since you're stuck with the hub being off center anyway] and that rim
looks symmetric to me.
> The reason for the aluminum
> spokes on the drive side in the rear wheel is so that they could use
> thin bladed spokes and thus place them as far away from the center of
> the hub as possible.
that might be true. but then again, the carbon spokes should be less
elastic, so that would mitigate their use...
> It lookes like the front wheel uses 18 spokes
> and the rear uses 24.
> It sounds like a decent racing wheel to me but I am a bit sceptical
> about how it will hold up for the general public. I did find this
> claim by mavic to be interesting, "In seeking that elusive "third
> generation", Mavic designers and engineers identified spoke stiffness
> and flange spacing as the biggest contributors to a wheel's lateral
> rigidity, while rim stiffness, spoke length, hub flange diameter, and
> spoke lacing patterns all are said to offer little significant
> influence.
well, bracing angle is the largest factor, but the other points contribute.
> More surprisingly, Mavic also claims that spoke tension has
> a negligible influence,
of course - tension does not affect stiffness. only if you read certain
books that are unclear on the concept could you get that impression.
> and increasing the spoke tension actually
> reduces overall lateral rigidity (although it does delay the onset of
> complete spoke detensioning)."
in that increasing tension brings the rim closer to buckling, that's true.
> I was surprised to hear that rim
> stiffness has such a small influence on lateral stiffness. I notice a
> huge difference between a deepV rim and a open pro rim when it comes
> to lateral stiffness, assuming the same hub and spokes are used in
> both wheels.
>
a stiffer rim makes a wheel stiffer for sure, but the effect is indeed
small compared to the effect of spoke bracing angle.
|
| | | |
Date: 27 Jun 2007 18:01:35
From: Ron Ruff
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 27, 6:32 pm, jobst.bra...@stanfordalumni.org wrote:
> Therefore, this argumentation is
> academic while in reality the ratios remain as good as constant.
The geometric ratios *do* remain constant for all practical
purposes... I don't think anyone is arguing otherwise. It's the
*tension* ratio that varies considerably.
|
| | | | |
Date: 28 Jun 2007 01:40:40
From:
Subject: Re: Mavic introduces wheel with compression spokes
|
Ron Ruff <rruffrruff@yahoo.com > writes:
>> Therefore, this argumentation is academic while in reality the
>> ratios remain as good as constant.
> The geometric ratios *do* remain constant for all practical
> purposes... I don't think anyone is arguing otherwise. It's the
> *tension* ratio that varies considerably.
The two go together. The force diagram is one and the same with the
physical triangle formed by spokes and hub, the forces being coaxial
with the spokes.
Jobst Brandt
|
| | | |
Date: 25 Jun 2007 12:52:20
From: Gary Young
Subject: Re: Mavic introduces wheel with compression spokes
|
On Mon, 25 Jun 2007 11:33:01 -0600, carlfogel wrote:
> On Mon, 25 Jun 2007 07:46:00 -0700, Joe Riel <joer@san.rr.com> wrote:
>
>>jim beam <spamvortex@bad.example.net> writes:
>>
>>> garyyoung3@gmail.com wrote:
>>>> On Jun 25, 2:28 am, garyyou...@gmail.com wrote:
>>>> <snip>
>>>>
>>>>> Exactly. It sounds to me as if Mavic has designed this wheel with
>>>>> tensions low enough that the right-side spokes routinely go slack with
>>>>> typical loads as they pass the contact patch. And consequently the
>>>>> left-side spokes lose all tension and compress as they pass the
>>>>> contact patch.
>>>>>
>>>>
>>>> Nah. I'm going to backtrack. It's only necessary that a typical load
>>>> make the left-side spokes go slack as they pass the contact patch. At
>>>> that point, they're free to go into compression even if the left-hand
>>>> spokes still have some tension.
>>>>
>>> impossible. tension ratio has to remain unless laterally loaded. see
>>> above.
>>
>>That's not immediately clear. Even with a pure radial load, the rim
>>has to deflect sideways (because of the unequal spoke angle
>>constraints). That locally bends the rim, which is equivalent to a
>>lateral force, more or less. It seems a reasonable approximation,
>>but... Did Damon Richard measure the tension change with a pure
>>radial load in an offset wheel?
>
> Dear Joe,
>
> http://www.sheldonbrown.com/rinard/wheel/index.htm
>
> Cheers,
>
> Carl Fogel
It looks like all of the wheels he tested had the same type of spokes left
and right. If so, how helpful would his results be in examining a wheel
with spokes of different materials left and right?
|
| | |
Date: 20 Jun 2007 15:07:35
From:
Subject: Re: Mavic introduces wheel with compression spokes
|
Steve Sauter writes:
http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html
>>> The description seems to me to be hopelessly confused, but there
>>> is a photograph showing how the carbon-fiber spokes connect to the
>>> hub.
>> well /this/
http://tinyurl.com/2m59r9
>> sure isn't a compression fitting!
> According to www.cyclingnews.com the carbon spokes are in tension
> but are designed to handle compressive loads as well. This allows
> them to make a wheel with lower spoke tension thus a lighter rim
> since it doesn't have to handle as much stress from the spokes.
> Mavic has also finally given in to the asymmetric rim design for
> there new wheels in order to help balance spoke tension. The reason
> for the aluminum spokes on the drive side in the rear wheel is so
> that they could use thin bladed spokes and thus place them as far
> away from the center of the hub as possible. It looks like the
> front wheel uses 18 spokes and the rear uses 24.
> It sounds like a decent racing wheel to me but I am a bit skeptical
> about how it will hold up for the general public.
I don't understand what the difference between racing and other
bicycling has for wheels. What is it a wheel must do in a race that
is different from non-race riding. I seem to see differences implied
that one is a greater stress than the other but the more stressful one
changes depending on what point is being put forth.
From what I see cruising up and down the avenue here, the all look
like racing wheels, some costing as much as $4000 a pair, according to
our local bicycle shops.
Jobst Brandt
|
| |
Date: 20 Jun 2007 07:20:50
From: Ozark Bicycle
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 20, 9:06 am, datakoll <datak...@yahoo.com > wrote:
<snipped >
- on Mavic's latest gimmick -
>
> Mavic says that a full compliment of tubular carbon spokes would make
> the rear wheel ride too rigid.
Mavic seems to have struck the Mother Lode of Unadulterated BS!
|
| |
Date: 20 Jun 2007 07:11:54
From: Qui si parla Campagnolo
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 19, 11:58 am, Kinky Cowboy <u...@domain.com > wrote:
> On Tue, 19 Jun 2007 07:41:12 -0700, Qui si parla Campagnolo
>
> <p...@vecchios.com> wrote:
> >On Jun 18, 9:55 pm, Gary Young <garyyou...@gmail.com> wrote:
> >> Road Mag's blog had this item today:
>
> >> "The [new] wheels, which are part of the Ksyrium family,>>
> >>http://tinyurl.com/2m59r9
>
> >Still with crappola rear hub and for only, what $2600 or so??
>
> >my head hurts
>
> "The suggested retail is about $1,400 US" according to the article.
>
> Also "(the spokes only way[sic] five grams each - versus an aluminium
> at eight grams "
>
> Sapim CX-Rays weight 4g, and are cheaper than Mavic Aluminium or
> carbon spokes. So instead of 16 carbon spokes, use 20 CX-Rays; I'm
> pretty sure that's going to make a wheel with both higher axial
> stiffness and lower aerodynamic drag, at exactly the same weight and
> lower cost. Is there some vital piece of European politics I'm missing
> which prevents French Mavic from admitting that Belgian Sapim (or
> Swiss DT) have already solved the spoke problem? Heck, both countries
> even have substantial Francophone populations, so it can't be a
> language issue.
>
> Kinky Cowboy*
>
> *Batteries not included
> May contain traces of nuts
> Your milage may vary
ahh, I see, take a Kry-4-me sirium, same crappy rear hub(even with red
pawls), replace left side rear spokes with carbon ones..make the rim
assymetric(a GOOD idea), add $300 to the price(ala 'ES version)..heads
still hurts. lesseeee...these 1400 grams or so..OR....use a DA/Record/
DT hubset, Velocity rims, DT spokes...$600-$750 or so and 1550 grams
or so...150 grams are now worth $700!!!
head still hurts...
|
| |
Date: 20 Jun 2007 14:06:41
From: datakoll
Subject: Re: Mavic introduces wheel with compression spokes
|
ahhhh!
BM writes: The drive side rear spokes are aluminum, like Ksyrium.
Mavic says that a full compliment of tubular carbon spokes would make
the rear wheel ride too rigid. Also, the aluminum spokes will tolerate
a derailleur or chain thrown into the spokes better and are cheaper to
replace if you do.
and off coursa this answers the first question after Ma tells us the
carbons donna bend.
insteda of bending the spokes...
sounds like a terrific idea. placement at speed. see the rider photo.
|
| |
Date: 20 Jun 2007 05:18:06
From: Ozark Bicycle
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 20, 7:11 am, Qui si parla Campagnolo <p...@vecchios.com > wrote:
> On Jun 19, 12:01 pm, Ozark Bicycle
>
>
>
>
>
> <bicycleatel...@ozarkbicycleservice.com> wrote:
> > On Jun 18, 11:33 pm, Michael Warner <m...@westnet.com.au> wrote:
>
> > > On Mon, 18 Jun 2007 22:55:51 -0500, Gary Young wrote:
> > > > the wheel via tension. I won't try and explain it in detail here - but the
> > > > general idea is that the carbon tubes give the wheel a lot more rigidity -
> > > > plus they are lighter....
>
> > > I'd say the general idea is to make them sound reassuring to fat
> > > weekend warriors :-)
>
> > Coming soon: the Ksyrium WBE (WannaBe Edition); almost as strong and
> > reliable as a conventional 32H wheel, but 25% heavier and 350% more
> > expensive. Of course, it will have the 'look', the 'cool factor', all
> > those colorful stickers, and a big red spoke. Just the thing at the
> > Latte Stop. ;-)
>
> http://www.elevengear.us/poseur.html-
Ain't that a hoot?
|
| |
Date: 20 Jun 2007 05:11:50
From: Qui si parla Campagnolo
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 19, 12:01 pm, Ozark Bicycle
<bicycleatel...@ozarkbicycleservice.com > wrote:
> On Jun 18, 11:33 pm, Michael Warner <m...@westnet.com.au> wrote:
>
> > On Mon, 18 Jun 2007 22:55:51 -0500, Gary Young wrote:
> > > the wheel via tension. I won't try and explain it in detail here - but the
> > > general idea is that the carbon tubes give the wheel a lot more rigidity -
> > > plus they are lighter....
>
> > I'd say the general idea is to make them sound reassuring to fat
> > weekend warriors :-)
>
> Coming soon: the Ksyrium WBE (WannaBe Edition); almost as strong and
> reliable as a conventional 32H wheel, but 25% heavier and 350% more
> expensive. Of course, it will have the 'look', the 'cool factor', all
> those colorful stickers, and a big red spoke. Just the thing at the
> Latte Stop. ;-)
http://www.elevengear.us/poseur.html
|
| |
Date: 20 Jun 2007 02:46:26
From: Gary Young
Subject: Re: Mavic introduces wheel with compression spokes
|
Another blog posting on the wheel:
http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html
The description seems to me to be hopelessly confused, but there is a
photograph showing how the carbon-fiber spokes connect to the hub.
|
| | |
Date: 20 Jun 2007 05:51:59
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
Gary Young wrote:
> Another blog posting on the wheel:
>
> http://thisjustin.bicycling.com/2007/06/new_mavic_wheel.html
>
> The description seems to me to be hopelessly confused, but there is a
> photograph showing how the carbon-fiber spokes connect to the hub.
well /this/
http://rodale.typepad.com/.shared/image.html?/photos/uncategorized/2007/06/19/img_1529.jpg
sure isn't a compression fitting!
|
| | | |
Date: 29 Jun 2007 08:02:30
From: Joe Riel
Subject: Re: Mavic introduces wheel with compression spokes
|
jim beam <spamvortex@bad.example.net > writes:
> yes, i'll buy that. needs eventually to have rim stiffness rolled in
> if you want to build the definitive model though.
Earlier I posted an expression that included factors for rim stiffness.
Cleverly I didn't define precisely what they meant, that was intentional.
Its purpose was to express the form of the equation rather than provide
a useful computational model.
The expression I posted here (not shown, in this post) is entirely
based on a two spoke planar model. Ignoring rim stiffness, that is
at best an approximation, since, of course, the other spokes have
an effect. Its purpose was to show that a radial force need not
result in a purely radial deflection.
--
Joe Riel
|
| | | |
Date: 28 Jun 2007 08:00:09
From: Joe Riel
Subject: Re: Mavic introduces wheel with compression spokes
|
jobst.brandt@stanfordalumni.org writes:
> I think this has all gotten out of reality by ignoring the dimensions
> involved. Spoke strain is in the 1/10 mm range and spoke length is in
> the 300 mm range. All the angular changes have trigonometric
> significance of 1/1000 or so. Therefore, this argumentation is
> academic while in reality the ratios remain as good as constant. So
> let's not lose track of practical effects, the ones on which we ride
> bike.
The issue at hand was whether a radial load caused a lateral movement
in an offset wheel. For a typical rear wheel, the lateral deflection
is significantly larger than the radial deflection (if my computations
are correct). I get
2 2 2 2
h (-w2 w1 - w2 h + w1 w2 + w1 h )
dx/dy := ------------------------------------
2 2 2 2 2 2
2 w2 w1 + w2 h + w1 h
where
w1 = distance from left flange to center plane of rim
w2 = distance from right flange to center plane of rim
h = wheel radius
dx/dy = ratio of lateral to radial deflection
Using
w1 = 38 mm
w2 = 18 mm
h = 300 mm
dx/dy = 3.4 (negative means the deflection is toward
Let the offset be dw, with w1 = w/2 + dw (w is flange to flange spacing).
Then, for small dw and h >> w
dx/dy = 4*h*dw/w^2
--
Joe Riel
|
| | | | |
Date: 28 Jun 2007 18:15:23
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
Joe Riel wrote:
> jobst.brandt@stanfordalumni.org writes:
>
>> I think this has all gotten out of reality by ignoring the dimensions
>> involved. Spoke strain is in the 1/10 mm range and spoke length is in
>> the 300 mm range. All the angular changes have trigonometric
>> significance of 1/1000 or so. Therefore, this argumentation is
>> academic while in reality the ratios remain as good as constant. So
>> let's not lose track of practical effects, the ones on which we ride
>> bike.
>
> The issue at hand was whether a radial load caused a lateral movement
> in an offset wheel. For a typical rear wheel, the lateral deflection
> is significantly larger than the radial deflection (if my computations
> are correct). I get
>
> 2 2 2 2
> h (-w2 w1 - w2 h + w1 w2 + w1 h )
> dx/dy := ------------------------------------
> 2 2 2 2 2 2
> 2 w2 w1 + w2 h + w1 h
>
>
> where
> w1 = distance from left flange to center plane of rim
> w2 = distance from right flange to center plane of rim
> h = wheel radius
> dx/dy = ratio of lateral to radial deflection
>
> Using
> w1 = 38 mm
> w2 = 18 mm
> h = 300 mm
>
> dx/dy = 3.4 (negative means the deflection is toward
>
> Let the offset be dw, with w1 = w/2 + dw (w is flange to flange spacing).
> Then, for small dw and h >> w
>
> dx/dy = 4*h*dw/w^2
>
>
yes, i'll buy that. needs eventually to have rim stiffness rolled in if
you want to build the definitive model though.
for the time being, i think two factors have higher precedence:
1. static tension ratio - it's a regular question here from newbie
builders as to why they can't get the tension on the nds higher. for
that, simple angle ratio geometry suffices as explanation.
2. in use, a much more important factor is lateral loading. i can
momentarily slacken the nds spokes on my mavic cosmos every pedal stroke
if i honk up a hill hard enough because of the lateral loads. that's
going to swamp anything else for tension ratios and has to be the #1
factor in design.
great work though joe.
|
| | | | |
Date: 28 Jun 2007 17:57:47
From:
Subject: Re: Mavic introduces wheel with compression spokes
|
Joe Riel writes:
>> I think this has all gotten out of reality by ignoring the
>> dimensions involved. Spoke strain is in the 1/10 mm range and
>> spoke length is in the 300 mm range. All the angular changes have
>> trigonometric significance of 1/1000 or so. Therefore, this
>> argumentation is academic while in reality the ratios remain as
>> good as constant. So let's not lose track of practical effects,
>> the ones on which we ride bike.
> The issue at hand was whether a radial load caused a lateral
> movement in an offset wheel. For a typical rear wheel, the lateral
> deflection is significantly larger than the radial deflection (if my
> computations are correct). I get
> 2 2 2 2
> h (-w2 w1 - w2 h + w1 w2 + w1 h )
> dx/dy := ------------------------------------
> 2 2 2 2 2 2
> 2 w2 w1 + w2 h + w1 h
However, I am not following your sums of squares here, maybe it's factored
obscurely or not enough delimiters.
<---------------- w -------------- >
<----- w/2 ----->
|
| | | | | |
Date: 30 Jun 2007 10:21:15
From: Luns Tee
Subject: Re: Mavic introduces wheel with compression spokes
|
In article <4683f69b$0$14088$742ec2ed@news.sonic.net >,
<jobst.brandt@stanfordalumni.org > wrote:
>With 0.1mm radial deflection, for a typical wheel in use just rolling
>along:
>
> 3.4 * 0.1mm = 0.34mm (0.013")
>
>Your equation yields <0.4mm lateral movement. No wonder we can't
>notice that and that it has no effect on wheel performance.
That we can't perceive the movement doesn't mean the effect is
irrelevant. Rear wheels with extra dish for 8-9-10 speed rear clusters
also have movement of similarly small magnitude, but you deprecate those
wheels. What matters isn't the magnitude of the motions but rather the
effect on tensions. In the present discussion, as I perceived it
earlier, the question is of whether left and right side spokes go slack
at the same time with radial loading, or if the left, being under less
tension to start with, goes slack first.
The rim in the radially deflected area wants to move this 0.4mm
towards the drive side. The rim elsewhere, where there is no radial
load or deflection, wants to stay where it was. Either the rim has to
somehow absorb this 0.4mm lateral difference, or else it exerts lateral
forces onto the spokes.
I believe that the latter happens, and that lateral stiffness
of the rim restrains the radially loaded section against this deflection.
In the radially affected region, the rim isn't allowed to deflect
laterally as much as it needs to to keep the ~2:1 tension ratio it
started with - the lateral force from the rim causes the left side
spokes to lose more tension, and the right side spokes less, than if
the rim were laterally flexible. The spokes outside the radially load
affected zone are what support the rim to provide this force, and they
get pushed the opposite way: with the left side spokes there
experiencing an increase in tension, and the right side spokes
decreasing.
The question of magnitudes is still open, but this is
where I think an FEA could be very valuable. I'm looking into whether
I can drum up access to FEA software, or better yet, someone familiar
with using it.
-Luns
|
| | | | | | |
Date: 30 Jun 2007 22:10:54
From: Luns Tee
Subject: Re: Mavic introduces wheel with compression spokes
|
In article <f65aqr$ebi$1@agate.berkeley.edu >,
Luns Tee <luns@mochi.EECS.Berkeley.EDU > wrote:
> I believe that the latter happens, and that lateral stiffness
>of the rim restrains the radially loaded section against this deflection.
>In the radially affected region, the rim isn't allowed to deflect
>laterally as much as it needs to to keep the ~2:1 tension ratio it
>started with - the lateral force from the rim causes the left side
>spokes to lose more tension, and the right side spokes less, than if
>the rim were laterally flexible. The spokes outside the radially load
>affected zone are what support the rim to provide this force, and they
>get pushed the opposite way: with the left side spokes there
>experiencing an increase in tension, and the right side spokes
>decreasing.
>
> The question of magnitudes is still open, but this is
>where I think an FEA could be very valuable. I'm looking into whether
>I can drum up access to FEA software, or better yet, someone familiar
>with using it.
I managed to find an FE model of a bicycle wheel in MATLAB
written by Eric Soroos about 12 years ago. Interestingly, it had popped
up in a discussion here as the last post in a thread, where Jim
Papodopoulos was saying pretty much the same things as I did in my
previous post. The code for solving the FE is credited to G. Miller, and
is used as part of a structural mechanics course at U. Washington - I
will guess that Eric's wheel model was connected to a class he was
taking there at the time, and not purely in response to discussions in
RBT.
I've taken Eric's model, and modified it slightly. His was
for a 3-cross wheel, but I've made it radial so as not to confuse things
with effects from lacing. I also reduced the dish somewhat - the
original model had flanges at 2.5" and 0.5" away from the rim plane -
I've made the spacings 2" and 1". I haven't verified the numbers for
bending moment of the rim, but the numbers used are given as being for
an MA-40 rim, with 32 2.0mm steel spokes.
The effect at the very bottom of the wheel are as I expected:
the reduction in spoke tension from wheel loading is not in the 2:1
ratio of the wheel dish. The ratio is closer to 4:3. This means that
under pure radial loading of the wheel, the left side spokes do go slack
before the right side.
As has been mentioned, having thinner left side spokes would
help this. Halving their sectional area to match the 2:1 dish would
eliminate lateral effects from radial loading and increase by about
30% the vertical load needed to make left spokes go slack.
-Luns
|
| | | | | | | |
Date: 30 Jun 2007 18:20:34
From: A Muzi
Subject: Re: Mavic introduces wheel with compression spokes
|
-snip-
Luns Tee wrote:
> I've made the spacings 2" and 1". I haven't verified the numbers for
> bending moment of the rim, but the numbers used are given as being for
> an MA-40 rim, with 32 2.0mm steel spokes.
-snip-
" two inches"
" one inch"
" 2.0mm"
As an aside, wouldn't it make sense to use either all inches or all CGS?
Do you commonly work in inches? Just curious.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | | | | | | | |
Date: 30 Jun 2007 23:50:55
From: Luns Tee
Subject: Re: Mavic introduces wheel with compression spokes
|
In article <138dpaq4jab2484@corp.supernews.com >,
A Muzi <am@yellowjersey.org > wrote:
>-snip-
>Luns Tee wrote:
>> I've made the spacings 2" and 1". I haven't verified the numbers for
>> bending moment of the rim, but the numbers used are given as being for
>> an MA-40 rim, with 32 2.0mm steel spokes.
>-snip-
>
>" two inches"
>" one inch"
>" 2.0mm"
>
>As an aside, wouldn't it make sense to use either all inches or all CGS?
>Do you commonly work in inches? Just curious.
I generally dislike using inch measures, and avoid them whenever
I can. However the wheel model as I received it implemented everything
in inches, and I wasn't about to re-work all the dimensions in it to
SI for the hell of it. I see no more harm in referring to the spokes
as 2.0mm than referring to people's height using feet or distances of
miles - while it's a different unit for the same dimension, it's also
a different scale, between which the ratios aren't necessarily useful.
I think people identify with 2.0mm as a spoke diameter better than
0.078740".
I'll give all the dimensions in furlongs next time.
-Luns
|
| | | | | | | | | |
Date: 30 Jun 2007 18:56:56
From: A Muzi
Subject: Re: Mavic introduces wheel with compression spokes
|
>> -snip-
>> Luns Tee wrote:
>>> I've made the spacings 2" and 1". I haven't verified the numbers for
>>> bending moment of the rim, but the numbers used are given as being for
>>> an MA-40 rim, with 32 2.0mm steel spokes.
>> -snip-
> A Muzi <am@yellowjersey.org> wrote:
>> " two inches"
>> " one inch"
>> " 2.0mm"
>> As an aside, wouldn't it make sense to use either all inches or all CGS?
>> Do you commonly work in inches? Just curious.
Luns Tee wrote:
> I generally dislike using inch measures, and avoid them whenever
> I can. However the wheel model as I received it implemented everything
> in inches, and I wasn't about to re-work all the dimensions in it to
> SI for the hell of it. I see no more harm in referring to the spokes
> as 2.0mm than referring to people's height using feet or distances of
> miles - while it's a different unit for the same dimension, it's also
> a different scale, between which the ratios aren't necessarily useful.
> I think people identify with 2.0mm as a spoke diameter better than
> 0.078740".
> I'll give all the dimensions in furlongs next time.
I wasn't carping, I just see inches so infrequently it caught my eye.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | | | | | | |
Date: 30 Jun 2007 15:43:09
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
Luns Tee wrote:
> In article <f65aqr$ebi$1@agate.berkeley.edu>,
> Luns Tee <luns@mochi.EECS.Berkeley.EDU> wrote:
>> I believe that the latter happens, and that lateral stiffness
>> of the rim restrains the radially loaded section against this deflection.
>> In the radially affected region, the rim isn't allowed to deflect
>> laterally as much as it needs to to keep the ~2:1 tension ratio it
>> started with - the lateral force from the rim causes the left side
>> spokes to lose more tension, and the right side spokes less, than if
>> the rim were laterally flexible. The spokes outside the radially load
>> affected zone are what support the rim to provide this force, and they
>> get pushed the opposite way: with the left side spokes there
>> experiencing an increase in tension, and the right side spokes
>> decreasing.
>>
>> The question of magnitudes is still open, but this is
>> where I think an FEA could be very valuable. I'm looking into whether
>> I can drum up access to FEA software, or better yet, someone familiar
>> with using it.
>
> I managed to find an FE model of a bicycle wheel in MATLAB
> written by Eric Soroos about 12 years ago. Interestingly, it had popped
> up in a discussion here as the last post in a thread, where Jim
> Papodopoulos was saying pretty much the same things as I did in my
> previous post. The code for solving the FE is credited to G. Miller, and
> is used as part of a structural mechanics course at U. Washington - I
> will guess that Eric's wheel model was connected to a class he was
> taking there at the time, and not purely in response to discussions in
> RBT.
>
> I've taken Eric's model, and modified it slightly. His was
> for a 3-cross wheel, but I've made it radial so as not to confuse things
> with effects from lacing. I also reduced the dish somewhat - the
> original model had flanges at 2.5" and 0.5" away from the rim plane -
> I've made the spacings 2" and 1". I haven't verified the numbers for
> bending moment of the rim, but the numbers used are given as being for
> an MA-40 rim, with 32 2.0mm steel spokes.
>
> The effect at the very bottom of the wheel are as I expected:
> the reduction in spoke tension from wheel loading is not in the 2:1
> ratio of the wheel dish. The ratio is closer to 4:3. This means that
> under pure radial loading of the wheel, the left side spokes do go slack
> before the right side.
>
> As has been mentioned, having thinner left side spokes would
> help this. Halving their sectional area to match the 2:1 dish would
> eliminate lateral effects from radial loading and increase by about
> 30% the vertical load needed to make left spokes go slack.
>
> -Luns
when you're ready, can you post a link? it would be good to check it out.
|
| | | | | | |
Date: 30 Jun 2007 12:38:29
From:
Subject: Re: Mavic introduces wheel with compression spokes
|
On Sat, 30 Jun 2007 10:21:15 +0000 (UTC), luns@mochi.EECS.Berkeley.EDU
(Luns Tee) wrote:
>In article <4683f69b$0$14088$742ec2ed@news.sonic.net>,
> <jobst.brandt@stanfordalumni.org> wrote:
>>With 0.1mm radial deflection, for a typical wheel in use just rolling
>>along:
>>
>> 3.4 * 0.1mm = 0.34mm (0.013")
>>
>>Your equation yields <0.4mm lateral movement. No wonder we can't
>>notice that and that it has no effect on wheel performance.
>
> That we can't perceive the movement doesn't mean the effect is
>irrelevant. Rear wheels with extra dish for 8-9-10 speed rear clusters
>also have movement of similarly small magnitude, but you deprecate those
>wheels. What matters isn't the magnitude of the motions but rather the
>effect on tensions. In the present discussion, as I perceived it
>earlier, the question is of whether left and right side spokes go slack
>at the same time with radial loading, or if the left, being under less
>tension to start with, goes slack first.
>
> The rim in the radially deflected area wants to move this 0.4mm
>towards the drive side. The rim elsewhere, where there is no radial
>load or deflection, wants to stay where it was. Either the rim has to
>somehow absorb this 0.4mm lateral difference, or else it exerts lateral
>forces onto the spokes.
>
> I believe that the latter happens, and that lateral stiffness
>of the rim restrains the radially loaded section against this deflection.
>In the radially affected region, the rim isn't allowed to deflect
>laterally as much as it needs to to keep the ~2:1 tension ratio it
>started with - the lateral force from the rim causes the left side
>spokes to lose more tension, and the right side spokes less, than if
>the rim were laterally flexible. The spokes outside the radially load
>affected zone are what support the rim to provide this force, and they
>get pushed the opposite way: with the left side spokes there
>experiencing an increase in tension, and the right side spokes
>decreasing.
>
> The question of magnitudes is still open, but this is
>where I think an FEA could be very valuable. I'm looking into whether
>I can drum up access to FEA software, or better yet, someone familiar
>with using it.
>
>-Luns
Dear Luns,
Ian might have suggestions or even be willing to look into the
question. Here's his page about his FEA wheel model:
http://www.astounding.org.uk/ian/wheel/model.html
And his main wheel page with results:
http://www.astounding.org.uk/ian/wheel/index.html
Cheers,
Carl Fogel
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Date: 27 Jun 2007 08:14:31
From: Ron Ruff
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 25, 11:22 pm, jim beam <spamvor...@bad.example.net > wrote:
> i already have. it's a fixed ratio. if y = 2x, you can't just go
> changing the 2 - which is what you're trying to suggest.
It isn't a fixed ratio... that is my point. Use Luns Tees string
example and do a simple force balance.
> because tension increases on the neighboring same-side spokes /and/ the
> rim displaces!
This also occurs when there is a pure radial load.
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Date: 28 Jun 2007 00:32:37
From:
Subject: Re: Mavic introduces wheel with compression spokes
|
Ron Ruff writes:
> It isn't a fixed ratio... that is my point. Use Luns Tees string
> example and do a simple force balance.
> This also occurs when there is a pure radial load.
I think this has all gotten out of reality by ignoring the dimensions
involved. Spoke strain is in the 1/10 mm range and spoke length is in
the 300 mm range. All the angular changes have trigonometric
significance of 1/1000 or so. Therefore, this argumentation is
academic while in reality the ratios remain as good as constant. So
let's not lose track of practical effects, the ones on which we ride
bike.
Jobst Brandt
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Date: 19 Jun 2007 20:42:09
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
Gary Young wrote:
> Road Mag's blog had this item today:
>
> "The [new] wheels, which are part of the Ksyrium family, use a combination
> of hollow carbon spokes (tubes) and the familiar aluminum spokes found on
> the Ksyrium. The front wheel has all carbon spokes and the real wheel has
> aluminum spokes on the drive (cassette) side and the carbon tubes on the
> none drive side. The carbon tubes act like a combination old fashion
> wooden spokes, which supported the wheel by compression (like a stiff
> wooden spoke on an ox cart) and traditional aluminum spokes that support
> the wheel via tension. I won't try and explain it in detail here - but the
> general idea is that the carbon tubes give the wheel a lot more rigidity -
> plus they are lighter....
>
> MAVIC brought out their machine for testing rigidity and put the wheel
> though it paces. They then ran another five wheels from various
> manufactures - these were all wheels that various journalists had brought
> along - so it was a pretty random cross section. The new MAVIC wheel came
> out on top. It was more rigid and at 1355 grams they are one of the
> lighter wheel sets on the market (hey - the spokes only way five grams
> each - versus an aluminum at eight grams - and we know that every gram
> counts)."
>
> =============================================
>
> The full item and photographs are at:
>
> http://roadmag.blogspot.com/2007/06/mavic-sprinters-and-climbers-take-note.html
>
> or
>
> http://tinyurl.com/2m59r9
>
> Notice that Mavic rolled out an old wooden wheel at the unveiling.
this was posted yesterday evening, but in the course of nearly 24 hours,
none of our "engineers" have picked up on the most, er, "interesting"
feature in the commentary:
"The carbon tubes act like a combination old fashion wooden spokes,
which supported the wheel by compression (like a stiff wooden spoke on
an ox cart) and traditional aluminum spokes that support the wheel via
tension."
this in the context of a rear wheel with drive side aluminum spokes and
non-drive side carbon i.e. supposedly tension one side, compression the
other.
now, if we know [and understand] our wheel theory, one could ask oneself
how it's possible to have tension on one side of a wheel and compression
on the other, right? any takers? come on, since this comes from an
anonymous and therefore non-credible liar, it should be easy to prove
this is a baseless and inflammatory question...
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Date: 20 Jun 2007 10:02:51
From: Kinky Cowboy
Subject: Re: Mavic introduces wheel with compression spokes
|
On Tue, 19 Jun 2007 20:42:09 -0700, jim beam
<spamvortex@bad.example.net > wrote:
>Gary Young wrote:
>> Road Mag's blog had this item today:
>>
>> " The carbon tubes act like a combination old fashion
>> wooden spokes, which supported the wheel by compression (like a stiff
>> wooden spoke on an ox cart) and traditional aluminum spokes that support
>> the wheel via tension
>
>this was posted yesterday evening, but in the course of nearly 24 hours,
>none of our "engineers" have picked up on the most, er, "interesting"
>feature in the commentary:
>
>"The carbon tubes act like a combination old fashion wooden spokes,
>which supported the wheel by compression (like a stiff wooden spoke on
>an ox cart) and traditional aluminum spokes that support the wheel via
>tension."
>
>this in the context of a rear wheel with drive side aluminum spokes and
>non-drive side carbon i.e. supposedly tension one side, compression the
>other.
>
>now, if we know [and understand] our wheel theory, one could ask oneself
>how it's possible to have tension on one side of a wheel and compression
>on the other, right? any takers? come on, since this comes from an
>anonymous and therefore non-credible liar, it should be easy to prove
>this is a baseless and inflammatory question...
We all knew that it was so blindingly obvious that either a: something
got lost in the translation or b: Mavic were demonstrating their
ignorance all over again that we wouldn't have to point it out even to
you.
Kinky Cowboy*
*Batteries not included
May contain traces of nuts
Your milage may vary
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Date: 20 Jun 2007 20:56:04
From: jim beam
Subject: Re: Mavic introduces wheel with compression spokes
|
Kinky Cowboy wrote:
> On Tue, 19 Jun 2007 20:42:09 -0700, jim beam
> <spamvortex@bad.example.net> wrote:
>
>> Gary Young wrote:
>>> Road Mag's blog had this item today:
>>>
>>> " The carbon tubes act like a combination old fashion
>>> wooden spokes, which supported the wheel by compression (like a stiff
>>> wooden spoke on an ox cart) and traditional aluminum spokes that support
>>> the wheel via tension
>> this was posted yesterday evening, but in the course of nearly 24 hours,
>> none of our "engineers" have picked up on the most, er, "interesting"
>> feature in the commentary:
>>
>> "The carbon tubes act like a combination old fashion wooden spokes,
>> which supported the wheel by compression (like a stiff wooden spoke on
>> an ox cart) and traditional aluminum spokes that support the wheel via
>> tension."
>>
>> this in the context of a rear wheel with drive side aluminum spokes and
>> non-drive side carbon i.e. supposedly tension one side, compression the
>> other.
>>
>> now, if we know [and understand] our wheel theory, one could ask oneself
>> how it's possible to have tension on one side of a wheel and compression
>> on the other, right? any takers? come on, since this comes from an
>> anonymous and therefore non-credible liar, it should be easy to prove
>> this is a baseless and inflammatory question...
>
> We all knew that it was so blindingly obvious that either a: something
> got lost in the translation or b: Mavic were demonstrating their
> ignorance all over again that we wouldn't have to point it out even to
> you.
>
you'da thunk, but judging by the other "blindingly obvious" things that
seem to be accepted without question, [tensiometer math, increasing
tension increases strength, etc.], you gotta wonder. especially as
another day passes without question of this thread's title.
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Date: 19 Jun 2007 11:01:44
From: Ozark Bicycle
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 18, 11:33 pm, Michael Warner <m...@westnet.com.au > wrote:
> On Mon, 18 Jun 2007 22:55:51 -0500, Gary Young wrote:
> > the wheel via tension. I won't try and explain it in detail here - but the
> > general idea is that the carbon tubes give the wheel a lot more rigidity -
> > plus they are lighter....
>
> I'd say the general idea is to make them sound reassuring to fat
> weekend warriors :-)
>
Coming soon: the Ksyrium WBE (WannaBe Edition); almost as strong and
reliable as a conventional 32H wheel, but 25% heavier and 350% more
expensive. Of course, it will have the 'look', the 'cool factor', all
those colorful stickers, and a big red spoke. Just the thing at the
Latte Stop. ;-)
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Date: 19 Jun 2007 07:41:12
From: Qui si parla Campagnolo
Subject: Re: Mavic introduces wheel with compression spokes
|
On Jun 18, 9:55 pm, Gary Young <garyyou...@gmail.com > wrote:
> Road Mag's blog had this item today:
>
> "The [new] wheels, which are part of the Ksyrium family, use a combination
> of hollow carbon spokes (tubes) and the familiar aluminum spokes found on
> the Ksyrium. The front wheel has all carbon spokes and the real wheel has
> aluminum spokes on the drive (cassette) side and the carbon tubes on the
> none drive side. The carbon tubes act like a combination old fashion
> wooden spokes, which supported the wheel by compression (like a stiff
> wooden spoke on an ox cart) and traditional aluminum spokes that support
> the wheel via tension. I won't try and explain it in detail here - but the
> general idea is that the carbon tubes give the wheel a lot more rigidity -
> plus they are lighter....
>
> MAVIC brought out their machine for testing rigidity and put the wheel
> though it paces. They then ran another five wheels from various
> manufactures - these were all wheels that various journalists had brought
> along - so it was a pretty random cross section. The new MAVIC wheel came
> out on top. It was more rigid and at 1355 grams they are one of the
> lighter wheel sets on the market (hey - the spokes only way five grams
> each - versus an aluminum at eight grams - and we know that every gram
> counts)."
>
> =============================================
>
> The full item and photographs are at:
>
> http://roadmag.blogspot.com/2007/06/mavic-sprinters-and-climbers-take...
>
> or
>
> http://tinyurl.com/2m59r9
>
> Notice that Mavic rolled out an old wooden wheel at the unveiling.
Still with crappola rear hub and for only, what $2600 or so??
my head hurts
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Date: 19 Jun 2007 18:58:17
From: Kinky Cowboy
Subject: Re: Mavic introduces wheel with compression spokes
|
On Tue, 19 Jun 2007 07:41:12 -0700, Qui si parla Campagnolo
<peter@vecchios.com > wrote:
>On Jun 18, 9:55 pm, Gary Young <garyyou...@gmail.com> wrote:
>> Road Mag's blog had this item today:
>>
>> "The [new] wheels, which are part of the Ksyrium family,>>
>> http://tinyurl.com/2m59r9
>>
>
>Still with crappola rear hub and for only, what $2600 or so??
>
>my head hurts
"The suggested retail is about $1,400 US" according to the article.
Also "(the spokes only way[sic] five grams each - versus an aluminium
at eight grams "
Sapim CX-Rays weight 4g, and are cheaper than Mavic Aluminium or
carbon spokes. So instead of 16 carbon spokes, use 20 CX-Rays; I'm
pretty sure that's going to make a wheel with both higher axial
stiffness and lower aerodynamic drag, at exactly the same weight and
lower cost. Is there some vital piece of European politics I'm missing
which prevents French Mavic from admitting that Belgian Sapim (or
Swiss DT) have already solved the spoke problem? Heck, both countries
even have substantial Francophone populations, so it can't be a
language issue.
Kinky Cowboy*
*Batteries not included
May contain traces of nuts
Your milage may vary
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Date: 22 Jun 2007 00:24:07
From: Kinky Cowboy
Subject: Re: Mavic introduces wheel with compression spokes
|
On Tue, 19 Jun 2007 18:58:17 +0100, Kinky Cowboy <user@domain.com >
wrote:
>
>Sapim CX-Rays weight 4g, and are cheaper than Mavic Aluminium or
>carbon spokes. So instead of 16 carbon spokes, use 20 CX-Rays; I'm
>pretty sure that's going to make a wheel with both higher axial
>stiffness and lower aerodynamic drag,
According to Roues Artisanales article
http://www.rouesartisanales.com//article-6833227.html
the new wheels have 35% more drag than the already poor Ksyrium ES.
That's going to be over 10W at 50km/h, which makes them nearly as bad
as an old fashioned Mavic Pro rim with 36 round spokes. At 25km/h up
an 8% slope, the excess drag compared with a cheap Shimano R560 would
be equivalent to a weight penalty of >0.5kg. The real weight of a pair
of R560s is 507g more than Mavic's claimed weight, although the $1000
saving could buy that weight back on any bike not yet troubled by the
UCI minimum.
Given that existing wheels are stiff enough, and ride comfort is about
tyres not wheels, the main advantage claimed by Mavic seems to be no
nipple unscrewing on unloaded nipples, a problem which seems to have
been solved years ago by eliminating spoke wind up at build and using
a thread locking compound for a belt and braces approach.
I'm not a Mavic hater, I race on their prebuilt wheels every week, but
they've really been hitting the crack pipe pretty hard to come up with
a wheel this bad and this expensive.
They're not only going to sell shitloads of these to gullible punters,
they're going to be inundated with requests for custom engraving like
the press launch wheels; if they have any sense, they'll add $500 for
custom engraving and laugh all the way to the bank.
Kinky Cowboy*
*Batteries not included
May contain traces of nuts
Your milage may vary
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Date: 19 Jun 2007 14:03:30
From: Michael Warner
Subject: Re: Mavic introduces wheel with compression spokes
|
On Mon, 18 Jun 2007 22:55:51 -0500, Gary Young wrote:
> the wheel via tension. I won't try and explain it in detail here - but the
> general idea is that the carbon tubes give the wheel a lot more rigidity -
> plus they are lighter....
I'd say the general idea is to make them sound reassuring to fat
weekend warriors :-)
--
Home page: http://members.westnet.com.au/mvw
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